Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Change in Plan Assets, Funded Status of the Plans, and Amounts Recognized in the Financial Statements Table (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Change in plan assets
Employer contributions	$ 58
Pension Plans, Defined Benefit [Member]
Change in plan assets
Fair value of plan assets at beginning of year	1,818	$ 1,754
Actual return on plan assets	16	111
Employer contributions	43	121
Participant contributions	0	1
Benefit payments	(194)	(159)
Foreign-currency exchange-rate changes	(9)	(10)
Fair value of plan assets at end of year	1,674	1,818
Funded status of the plans at end of year	(757)	(710)
Total recognized amounts in the balance sheet consist of
Other assets	41	41
Accrued expenses	(24)	(24)
Other long-term liabilities—other	(774)	(727)
Total	(757)	(710)
Total recognized amounts in accumulated other comprehensive income consist of
Prior service cost (credit)	(1)	(1)
Net actuarial (gain) loss	655	740
Total	654	739
Other Postretirement Benefit Plans, Defined Benefit [Member]
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	15	15
Participant contributions	5	4
Benefit payments	(20)	(19)
Foreign-currency exchange-rate changes	0	0
Fair value of plan assets at end of year	0	0
Funded status of the plans at end of year	(266)	(373)
Total recognized amounts in the balance sheet consist of
Other assets	0	0
Accrued expenses	(16)	(15)
Other long-term liabilities—other	(250)	(358)
Total	(266)	(373)
Total recognized amounts in accumulated other comprehensive income consist of
Prior service cost (credit)	(84)	2
Net actuarial (gain) loss	(25)	1
Total	$ (109)	$ 3