Segment Information (Reconciliation to consolidated operating income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	$ 87	$ 30
Unallocated restructuring charge	0	(1)
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	97	31
Unallocated Amount to Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Unallocated RSC merger related costs	(10)	0
Unallocated restructuring charge	$ 0	$ (1)