Commitments And Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Commitments And Contingencies [Abstract]
Estimated payments to the third-party providers	$ 232
Significant purchase commitment termination fee		$ 28	$ 34

The minimum amount the entity agreed to spend under the long-term purchase commitment.

No definition available.

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration