Commitments And Contingencies (Details) (USD $) In Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2010	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010
Commitments And Contingencies
Estimated payments to the third-party providers	$ 240
Significant purchase commitment termination fee			34	39
Escrow hold back for gain contingency		$ 9