Quarterly report pursuant to Section 13 or 15(d)

Activity in Accumulated Other Comprehensive Income (Loss) (Phantoms) (Detail)

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Activity in Accumulated Other Comprehensive Income (Loss) (Phantoms) (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Accumulated Other Comprehensive Income (Loss), Net of Tax $ (4,224) $ (3,651) $ (4,224) $ (3,651) $ (4,483)  
Change in foreign currency translation adjustment, net of tax 32 (7) 86 (12)    
Foreign currency translation gain (loss):            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Accumulated Other Comprehensive Income (Loss), Net of Tax (930) (909) (930) (909) (1,016) $ (897)
Change in foreign currency translation adjustment, net of tax     86 (12)    
Aggregate adjustment for the period, tax     (146) 24    
Unrealized gain (loss) on marketable securities, net of tax:            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Accumulated Other Comprehensive Income (Loss), Net of Tax 0 3 0 3 (1) (1)
Current period changes in fair value, tax effect     1 3    
Reclassification to earnings, tax effect     0 0    
Unrealized gain (loss) on cash flow hedges, net of tax:            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Accumulated Other Comprehensive Income (Loss), Net of Tax (323) (116) (323) (116) (45) 67
Current period changes in fair value, tax effect     (162) (15)    
Reclassification to earnings, tax effect     (6) (96)    
Accumulated Defined Benefit Plans Adjustment [Member]            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Accumulated Other Comprehensive Income (Loss), Net of Tax $ (2,971) $ (2,629) (2,971) (2,629) $ (3,421) $ (2,709)
Reclassification to earnings, tax effect     56 48    
Other Comprehensive Income (Loss), Finalization of Pension and Other Postretirement Benefit Plan Valuation, Tax     $ 214 $ 0