Derivative Instruments (Gains (Losses) On Derivative Instruments Designated As Cash Flow Hedges) (Details) - Designated as Hedging Instrument [Member] - Cash flow hedges - Other Comprehensive Income (Loss) [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Gains (losses) on derivative instruments designated and qualifying as cash flow hedges
Offset to net investment income	$ 3	$ 3
Offset to realized gain (loss)	$ 4
Offset to interest and debt expense		$ 1