Shares And Stockholders' Equity (Schedule of Reclassifications Out Of AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total realized gain (loss)	$ (7)	$ (10)	$ 5	$ (49)
Net investment income	1,232	1,262	2,465	2,499
Interest and debt expense	(68)	(63)	(159)	(127)
Commissions and other expenses	$ (1,177)	$ (1,034)	(2,234)	(2,048)
Unrealized Gain (Loss) on AFS Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total realized gain (loss)			(29)	(13)
Reclassifications before income tax benefit (expense)			(39)	(24)
Income tax benefit (expense)			8	8
Reclassifications, net of income tax			(31)	(16)
Unrealized Gain (Loss) on AFS Securities [Member] | Associated amortization of DAC, VOBA, DSI and DFEL [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total realized gain (loss)			(10)	(11)
Unrealized OTTI on AFS Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total realized gain (loss)				(1)
Reclassifications before income tax benefit (expense)				(1)
Reclassifications, net of income tax				(1)
Unrealized Gain (Loss) on Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Nonoperating income expense			11	7
Reclassifications before income tax benefit (expense)			10	5
Income tax benefit (expense)			(2)	(2)
Reclassifications, net of income tax			8	3
Unrealized Gain (Loss) on Derivative Instruments [Member] | Interest rate contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment income			2	2
Interest and debt expense			(2)	(9)
Unrealized Gain (Loss) on Derivative Instruments [Member] | Foreign currency contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total realized gain (loss)				5
Net investment income			11	9
Unrealized Gain (Loss) on Derivative Instruments [Member] | Associated amortization of DAC, VOBA, DSI and DFEL [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Commissions and other expenses			$ (1)	$ (2)