Employee Benefit Plans (Change in Fair Value of Company's Level 3 Pension Assets) (Detail) - Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	$ 635	$ 612
Realized gain	29	16
Unrealized gain/(loss) for positions still held	(16)	8
Transfers in/(out)	(77)	13
Foreign currency loss	(56)	(14)
End balance	515	635
Real Estate
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	209	210
Realized gain	28	15
Unrealized gain/(loss) for positions still held	(15)	12
Transfers in/(out)	(88)	(24)
Foreign currency loss	(5)	(4)
End balance	129	209
Other Debt Securities
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	21	23
Realized gain	1	1
Unrealized gain/(loss) for positions still held	0	0
Transfers in/(out)	(5)	(1)
Foreign currency loss	(1)	(2)
End balance	16	21
Hedge Funds & Other Assets
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	405	379
Realized gain	0	0
Unrealized gain/(loss) for positions still held	(1)	(4)
Transfers in/(out)	16	38
Foreign currency loss	(50)	(8)
End balance	$ 370	$ 405