Derivatives and Hedging Activities Derivatives and Hedging Activities (Amount of Gain (Loss) Recognized/Reclassified) (Details 8) (Cash Flow Hedging [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	$ (1)	$ (1)	$ 1
Other revenues [Member]
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income			3
Interest and debt expense [Member]
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	4	4	4
Net investment income [Member]
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	(5)	(5)	(6)
Interest on debt [Member]
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized in other comprehensive income (loss) on derivatives			$ 14