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, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Pension Plans, Defined Benefit [Member]
Change in plan assets
Fair value of plan assets at beginning of year	$ 1,754	$ 1,462
Actual return on plan assets	111	278
Employer contributions	121	160
Participant contributions	1	0
Benefit payments	(159)	(149)
Foreign-currency exchange-rate changes	(10)	3
Fair value of plan assets at end of year	1,818	1,754
Funded status of the plans at end of year	(710)	(404)
Total recognized amounts in the balance sheet consist of
Other assets	41	37
Accrued expenses	(24)	(19)
Other long-term liabilities—other	(727)	(422)
Total	(710)	(404)
Total recognized amounts in accumulated other comprehensive income consist of
Prior service cost (credit)	(1)	(1)
Net actuarial (gain) loss	740	441
Total	739	440
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	14
Participant contributions	4	4
Benefit payments	(19)	(18)
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	(373)	(294)
Total recognized amounts in the balance sheet consist of
Other assets	0	0
Accrued expenses	(15)	(15)
Other long-term liabilities—other	(358)	(279)
Total	(373)	(294)
Total recognized amounts in accumulated other comprehensive income consist of
Prior service cost (credit)	2	2
Net actuarial (gain) loss	1	(78)
Total	$ 3	$ (76)