Derivative Instruments and Hedging Activities Level 4 (Details) - CF Hedges Loss in OCI 3 mos & YTD (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Interest Rate Cash Flow Hedge Loss to be Reclassified During Next 12 Months, Net	$ 1		$ 1
Amount of Loss Recognized in OCI on Derivative - Interest swap - 2010	0	(2)	0	(2)
Amount of Loss Reclassified from Accumulated OCI into Income - Interest swap - 2010	$ (1)	$ (1)	$ (1)	$ (2)