Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity [Abstract]
Unrealized gains on available-for-sale securities, beginning balance	$ 11	$ 7	$ 6
Unrealized gains on available-for-sale securities, net of income taxes	(4)	4	1
Unrealized gains on available-for-sale securities, ending balance	7	11	7
Foreign currency translation adjustments, beginning balance	(1)	(25)	(19)
Foreign currency translation adjustments	12	24	(6)
Foreign currency translation adjustments, ending balance	11	(1)	(25)
Defined benefit plans, beginning balance	(196)	(169)	(143)
Defined benefit plans	84	(56)	(42)
Defined benefit plans, (income) expense reclassified into operations from other comprehensive income	24	29	16
Defined benefit plans, ending balance	(88)	(196)	(169)
Change in fair value of derivative instruments, beginning balance	(271)	(253)	(272)
Change in fair value of derivative instruments	2	(96)	(197)
Change in fair value of derivatives instruments, (income) expense reclassified into operations from other comprehensive income	82	78	216
Change in fair value of derivative instruments, ending balance	(187)	(271)	(253)
Accumulated other comprehensive income (loss), net of tax, beginning balance	(457)	(440)	(428)
Unrealized gains on available-for-sale securities, net of income taxes	(4)	4	1
Foreign currency translation adjustments	12	24	(6)
Defined benefit plans	84	(56)	(42)
Change in fair value of derivative instruments, net of income tax benefit	2	(96)	(197)
Expense reclassified into operations from other comprehensive income, Total	106	107	232
Accumulated other comprehensive income (loss), net of tax, Ending balance	$ (257)	$ (457)	$ (440)