Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allocation of other comprehensive income (loss)
Unrecognized components of net periodic benefit costs	$ (52)	$ (204)	$ (8)
Unrecognized gain (loss) on derivative instruments	3	(13)	(29)
Unrecognized loss on marketable securities		(13)
Recognized components of net periodic benefit costs	47	25	16
Recognized (gain) loss on derivative instruments	(1)	11	12
Recognized loss on marketable security	2	13
Other comprehensive income (loss) before income taxes	(1)	(181)	(9)
Income taxes related to other comprehensive income (loss)	(7)	13	(9)
Other comprehensive income (loss), net of income taxes	(8)	(168)	(18)
Controlling interest
Allocation of other comprehensive income (loss)
Unrecognized components of net periodic benefit costs	(52)	(204)	(8)
Unrecognized gain (loss) on derivative instruments	6	3	(10)
Unrecognized loss on marketable securities		(13)
Recognized components of net periodic benefit costs	47	25	16
Recognized (gain) loss on derivative instruments	(4)	(1)	14
Recognized loss on marketable security	2	13
Other comprehensive income (loss) before income taxes	(1)	(177)	12
Income taxes related to other comprehensive income (loss)	(7)	13	(9)
Other comprehensive income (loss), net of income taxes	(8)	(164)	3
Non-controlling interest and Redeemable non-controlling interest
Allocation of other comprehensive income (loss)
Unrecognized gain (loss) on derivative instruments	(3)	(16)	(19)
Recognized (gain) loss on derivative instruments	3	12	(2)
Other comprehensive income (loss) before income taxes		(4)	(21)
Other comprehensive income (loss), net of income taxes		$ (4)	$ (21)