Carrying Value of Outstanding Debt (Detail) - USD ($)
|
3 Months Ended |
|
Mar. 31, 2019 |
Dec. 31, 2018 |
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 23,312,000,000
|
|
| Debt instrument, stated interest rate |
8.375%
|
|
| Total debt |
$ 23,166,000,000
|
$ 22,736,000,000
|
| Less current maturities |
(2,789,000,000)
|
(2,805,000,000)
|
| Long-Term Debt and Finance Leases |
20,377,000,000
|
19,931,000,000
|
| Commercial Paper |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,644,000,000
|
|
| Maturity - Minimum Date |
Mar. 31, 2019
|
|
| Maturity - Maximum Date |
Dec. 31, 2020
|
|
| Total debt |
$ 1,644,000,000
|
2,662,000,000
|
| Senior notes | 5.50% stated rate |
|
|
| Debt Instrument [Line Items] |
|
|
| Maturity - Maximum Date |
Dec. 31, 2018
|
|
| Debt instrument, stated interest rate |
5.50%
|
|
| Senior notes | 5.125% stated rate |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,000,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2019
|
|
| Debt instrument, stated interest rate |
5.125%
|
|
| Total debt |
$ 1,000,000,000
|
998,000,000
|
| Senior notes | 3.125% stated rate |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2021
|
|
| Debt instrument, stated interest rate |
3.125%
|
|
| Total debt |
$ 1,522,000,000
|
1,492,000,000
|
| Senior notes | 2.050% senior notes [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 700,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2021
|
|
| Debt instrument, stated interest rate |
2.05%
|
|
| Total debt |
$ 698,000,000
|
698,000,000
|
| Senior notes | 2.400% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2026
|
|
| Debt instrument, stated interest rate |
2.40%
|
|
| Total debt |
$ 498,000,000
|
498,000,000
|
| Senior notes | 3.050% senior notes [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,000,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2027
|
|
| Debt instrument, stated interest rate |
3.05%
|
|
| Total debt |
$ 991,000,000
|
991,000,000
|
| Senior notes | 3.400% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 750,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2029
|
|
| Debt instrument, stated interest rate |
3.40%
|
|
| Total debt |
$ 745,000,000
|
0
|
| Senior notes | 2.45% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,000,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2022
|
|
| Debt instrument, stated interest rate |
2.45%
|
|
| Total debt |
$ 983,000,000
|
1,023,000,000
|
| Senior notes | 2.350% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 600,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2022
|
|
| Debt instrument, stated interest rate |
2.35%
|
|
| Total debt |
$ 598,000,000
|
597,000,000
|
| Senior notes | 2.500% senior notes [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,000,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2023
|
|
| Debt instrument, stated interest rate |
2.50%
|
|
| Total debt |
$ 994,000,000
|
994,000,000
|
| Senior notes | 2.800% senior notes [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2024
|
|
| Debt instrument, stated interest rate |
2.80%
|
|
| Total debt |
$ 496,000,000
|
496,000,000
|
| Senior notes | 6.20% stated rate |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2038
|
|
| Debt instrument, stated interest rate |
6.20%
|
|
| Total debt |
$ 1,482,000,000
|
1,482,000,000
|
| Senior notes | 4.875% stated rate |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2040
|
|
| Debt instrument, stated interest rate |
4.875%
|
|
| Total debt |
$ 490,000,000
|
490,000,000
|
| Senior notes | 3.625% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 375,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2042
|
|
| Debt instrument, stated interest rate |
3.625%
|
|
| Total debt |
$ 368,000,000
|
368,000,000
|
| Senior notes | 3.400% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2046
|
|
| Debt instrument, stated interest rate |
3.40%
|
|
| Total debt |
$ 491,000,000
|
491,000,000
|
| Senior notes | 3.750% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,150,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2047
|
|
| Debt instrument, stated interest rate |
3.75%
|
|
| Total debt |
$ 1,136,000,000
|
1,136,000,000
|
| Senior notes | 4.250% senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 750,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2049
|
|
| Debt instrument, stated interest rate |
4.25%
|
|
| Total debt |
$ 742,000,000
|
0
|
| Senior notes | Floating Rate Senior Notes 2 [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 350,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2021
|
|
| Total debt |
$ 349,000,000
|
349,000,000
|
| Senior notes | 8.375% debentures |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 424,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2020
|
|
| Debt instrument, stated interest rate |
8.375%
|
|
| Total debt |
$ 432,000,000
|
419,000,000
|
| Senior notes | 8.375% debentures |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 276,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2030
|
|
| Total debt |
$ 281,000,000
|
274,000,000
|
| Senior notes | Canadian senior note 2.125% |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 558,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2024
|
|
| Debt instrument, stated interest rate |
2.125%
|
|
| Total debt |
$ 555,000,000
|
548,000,000
|
| Senior notes | Floating rate senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 400,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2022
|
|
| Total debt |
$ 399,000,000
|
399,000,000
|
| Senior notes | Floating Rate Senior Notes 3 [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 500,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2023
|
|
| Total debt |
$ 499,000,000
|
499,000,000
|
| Senior notes | Floating Rate Senior Notes 4 [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 1,041,000,000
|
|
| Maturity - Minimum Date |
Dec. 31, 2049
|
|
| Maturity - Maximum Date |
Dec. 31, 2067
|
|
| Total debt |
$ 1,028,000,000
|
1,029,000,000
|
| Capital Lease Obligations |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 525,000,000
|
|
| Maturity - Minimum Date |
Dec. 31, 2019
|
|
| Maturity - Maximum Date |
Dec. 31, 3005
|
|
| Total debt |
$ 525,000,000
|
534,000,000
|
| Pound Sterling notes | 5.500% notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 87,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2031
|
|
| Debt instrument, stated interest rate |
5.50%
|
|
| Total debt |
$ 86,000,000
|
84,000,000
|
| Pound Sterling notes | 5.125% notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 595,000,000
|
|
| Maturity - Maximum Date |
Jan. 01, 2050
|
|
| Debt instrument, stated interest rate |
5.125%
|
|
| Total debt |
$ 564,000,000
|
546,000,000
|
| Euro Senior Notes | 0.375% Euro Senior Notes [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 786,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2023
|
|
| Debt instrument, stated interest rate |
0.375%
|
|
| Total debt |
$ 782,000,000
|
797,000,000
|
| Euro Senior Notes | 1.625% Euro Senior Notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 786,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2025
|
|
| Debt instrument, stated interest rate |
1.625%
|
|
| Total debt |
$ 782,000,000
|
798,000,000
|
| Euro Senior Notes | 1.000% notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 562,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2028
|
|
| Debt instrument, stated interest rate |
1.00%
|
|
| Total debt |
$ 558,000,000
|
570,000,000
|
| Euro Senior Notes | 1.500% Euro Senior Notes [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 562,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2032
|
|
| Debt instrument, stated interest rate |
1.50%
|
|
| Total debt |
$ 558,000,000
|
569,000,000
|
| Euro Senior Notes | Floating-rate senior notes |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 562,000,000
|
|
| Maturity - Maximum Date |
Dec. 31, 2020
|
|
| Total debt |
$ 561,000,000
|
572,000,000
|
| Facility notes and bonds |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 320,000,000
|
|
| Maturity - Minimum Date |
Dec. 31, 2029
|
|
| Maturity - Maximum Date |
Dec. 31, 2045
|
|
| Total debt |
$ 320,000,000
|
320,000,000
|
| Other debt |
|
|
| Debt Instrument [Line Items] |
|
|
| Debt Instrument, Face Amount |
$ 9,000,000
|
|
| Maturity - Minimum Date |
Dec. 31, 2019
|
|
| Maturity - Maximum Date |
Dec. 31, 2022
|
|
| Total debt |
$ 9,000,000
|
$ 13,000,000
|