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
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Accumulated Other Comprehensive Income (Loss), Net of Tax $ (4,462) $ (3,647) $ (4,483)  
Change in foreign currency translation adjustment, net of tax 30 26    
Foreign currency translation gain (loss):        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Accumulated Other Comprehensive Income (Loss), Net of Tax (986) (871) (1,016) $ (897)
Change in foreign currency translation adjustment, net of tax 30 26    
Aggregate adjustment for the period, tax (14) 0    
Unrealized gain (loss) on marketable securities, net of tax:        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Accumulated Other Comprehensive Income (Loss), Net of Tax (1) 2 (1) (1)
Current period changes in fair value, tax effect 0 2    
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 (86) (95) (45) 67
Current period changes in fair value, tax effect (17) (60)    
Reclassification to earnings, tax effect (7) (38)    
Accumulated Defined Benefit Plans Adjustment [Member]        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Accumulated Other Comprehensive Income (Loss), Net of Tax (3,389) (2,683) $ (3,421) $ (2,709)
Reclassification to earnings, tax effect 18 17    
Other Comprehensive Income (Loss), Finalization of Pension and Other Postretirement Benefit Plan Valuation, Tax $ 0 $ 0