Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2012		$ 15	$ (1,092)	$ 16,429	$ (8,449)	$ (33)
Balance (Shares) at Dec. 31, 2012		1,542,347,188
Net income (loss)	$ (121)				(121)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment	10					10
Net change in unrealized gains and losses on derivative financial instruments, net of tax	107					107
Net change in unrealized costs associated with certain retirement plans	22					22
Impact of stock-based compensation plans, net of tax (Shares)		17,955,446
Stock Issued During Period, Value, New Issues		$ 1
Impact of stock-based compensation plans, net of tax				150
Acquisition of treasury stock			(500)
Balance (Shares) at Dec. 31, 2013		1,560,302,634
Balance at Dec. 31, 2013		$ 16	(1,592)	16,579	(8,570)	106
Net income (loss)	(119)				(119)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment	(22)					(22)
Net change in unrealized gains and losses on derivative financial instruments, net of tax	78					78
Net change in unrealized costs associated with certain retirement plans	$ (18)					(18)
Impact of stock-based compensation plans, net of tax (Shares)		14,715,602
Stock Issued During Period, Value, New Issues		$ 0
Impact of stock-based compensation plans, net of tax				124
Acquisition of treasury stock			(125)
Balance (Shares) at Dec. 31, 2014	1,575,018,236	1,575,018,236
Balance at Dec. 31, 2014	$ 6,457	$ 16	(1,717)	16,703	(8,689)	144
Net income (loss)	(239)				(239)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment	(16)					(16)
Net change in unrealized gains and losses on derivative financial instruments, net of tax	(67)					(67)
Net change in unrealized costs associated with certain retirement plans	$ 27					27
Impact of stock-based compensation plans, net of tax (Shares)		19,195,550
Stock Issued During Period, Value, New Issues		$ 0
Impact of stock-based compensation plans, net of tax				157
ProfitLossDueToRounding					1
Acquisition of treasury stock			0
Balance (Shares) at Dec. 31, 2015	1,594,213,786	1,594,213,786
Balance at Dec. 31, 2015	$ 6,320	$ 16	$ (1,717)	$ 16,860	$ (8,927)	$ 88