Derivatives and Hedging Activities (Income Statement) (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net investment income [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	$ 5	$ (7)	$ 22	$ (4)
Net investment income [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	5	(8)	22	(7)
Net investment income [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income		1		3
Banking and deposit interest expense [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	0	0	1	0
Banking and deposit interest expense [Member] | SMC embedded derivatives [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(1)	(1)		(2)
Banking and deposit interest expense [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	1	1	1	2
Distribution expenses [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	8	9	5	25
Distribution expenses [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	8	8	5	23
Distribution expenses [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income		1		2
Interest credited to fixed accounts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(3)	1	25	13
Interest credited to fixed accounts [Member] | IUL embedded derivatives [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(14)	(12)	22	(19)
Interest credited to fixed accounts [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	11	13	3	32
Benefits, claims, losses and settlement expenses [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(175)	(168)	(254)	(317)
Benefits, claims, losses and settlement expenses [Member] | GMWB and GMAB embedded derivatives [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	96	(84)	376	342
Benefits, claims, losses and settlement expenses [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(135)	128	(533)	47
Benefits, claims, losses and settlement expenses [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(137)	(197)	(112)	(659)
Benefits, claims, losses and settlement expenses [Member] | Derivatives not designated as hedging instruments [Member] | Credit contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	6	(11)	18	(19)
Benefits, claims, losses and settlement expenses [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(3)	(4)	(1)	(28)
Benefits, claims, losses and settlement expenses [Member] | Derivatives not designated as hedging instruments [Member] | Other contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(2)		(2)
General and administrative expense [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	(4)	5	(6)	9
General and administrative expense [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	2	2	2	5
General and administrative expense [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Impact of derivatives not designated as hedging instruments on Consolidated Statements of Income
Amount of gain (loss) on derivatives recognized in income	$ (6)	$ 3	$ (8)	$ 4