Derivative Instruments (Gains (Losses) On Derivative Instruments Designated As Cash Flow Hedges) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Gains (losses) on derivative instruments designated and qualifying as cash flow hedges
Offset to net investment income	$ 1,355	$ 1,232	$ 2,606	$ 2,465
Offset to interest and debt expense	$ (70)	(68)	$ (141)	(159)
Designated as Hedging Instrument [Member] | Cash Flow Hedges [Member] | Other Comprehensive Income (Loss) [Member]
Gains (losses) on derivative instruments designated and qualifying as cash flow hedges
Offset to net investment income		6		13
Offset to interest and debt expense		$ 2		$ (2)