Derivatives and Hedging Activities (Impact of Hedging Activity) (Details 5) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Cash flow hedges [Member]
Derivative Instruments, Gain (Loss)
Estimated reclassification of net pretax losses on cash flow hedges from accumulated other comprehensive income to earnings during the next 12 months			$ 1
Cash flow hedge gain to be reclassified within twelve months to interest and debt expense			5
Cash flow hedge loss to be reclassified within twelve months recorded in net investment income			6
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	(1)	(1)	(1)	(1)
Longest period of time over which the entity hedges exposure to the variability in future cash flows			21 years
Cash flow hedges [Member] | Interest and debt expense [Member]
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	1	2	3	3
Cash flow hedges [Member] | Net investment income [Member]
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	(2)	(3)	(4)	(4)
Fair value hedges [Member]
Derivative Instruments, Gain (Loss)
Number of interest rate swaps held	3		3
Fair value hedges [Member] | Fixed rate debt [Member] | Interest and debt expense [Member]
Derivative Instruments, Gain (Loss)
Amount of gain recognized in income on derivatives	$ 9	$ 20	$ 25	$ 30