Debt (Debt Extinguishment) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Aug. 31, 2012 Senior Notes [Member]	Aug. 31, 2012 9.25% Note [Member] Senior Notes [Member]	Aug. 31, 2012 9.70% Note [Member] Senior Notes [Member]	Aug. 31, 2012 4.25% Note [Member]	Aug. 31, 2012 2.85% Note [Member]
Debt Instruments [Abstract]
Debt principal amount								$ 900,000,000	$ 1,900,000,000
Interest rate						9.25%	9.70%	4.25%	2.85%
Repurchase of debt					2,000,000,000	849,000,000	1,151,000,000
Loss on early extinguishment of debt	0	874,000,000	0	874,000,000
Tender premium and fees				864,000,000
Write off of deferred debt issuance cost and unamortized discount (premium)				$ 10,000,000