Debt (Narrative) (Details) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended			0 Months Ended				0 Months Ended	3 Months Ended	12 Months Ended
	Oct. 13, 2011	Feb. 28, 2011 Years	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jul. 15, 2011 Senior Debt Obligations Due 2014 [Member]	Dec. 31, 2011 Senior Debt Obligations Due 2014 [Member]	Jun. 27, 2011 Senior Debt Obligations Due 2014 [Member]	Sep. 30, 2010 Senior Debt Obligations Due 2010 [Member]	Jul. 15, 2011 Senior Debt Obligations Due 2015 [Member]	Sep. 30, 2011 Senior Debt Obligations Due In Ten Years [Member]	Dec. 31, 2011 September 2011 Debt Obligation [Member]	Oct. 13, 2011 September 2011 Debt Obligation [Member]
Debt instrument, interest rate, stated percentage								5.375%	5.15%		4.80%
Senior notes			$ 2,668,000,000	$ 3,026,000,000		$ 600,000,000			$ 550,000,000
Line of Credit Facility Term												5 years
Revised Purchase Price Allocation For Principal Amount Outstanding of Notes						330,000,000				270,000,000
Number of interest rate swaps		2
Floating rate three-month LIBOR plus fixed spread interest percentage		3.726%
Interest rate swaps, fair value adjustment		0
Swap agreements, effectiveness recognized during the period			0
Interest rate swap for hedging		125,000,000
Interest rate swap maturity, in years		3.5
Revolving credit facility, initiation date	October 13, 2011
5.375% senior notes due in 2014, hedged value							250,000,000
Line of credit facility, current borrowing capacity	1,000,000,000												1,000,000,000
Revolving credit facility, amount outstanding			0
Proceeds from issuance of debt			496,000,000		398,000,000						500,000,000
Debtor-in-Possession Financing, Letters of Credit Outstanding			$ 248,000,000	$ 272,000,000