Derivatives and Hedging Activities (Income Statement) (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net investment income [Member] | Derivatives not designated as hedging instruments [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	$ (13)	$ 2	$ (16)
Net investment income [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(3)	3	(21)
Net investment income [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(10)	(1)
Net investment income [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income			4
Net investment income [Member] | Derivatives not designated as hedging instruments [Member] | Other contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income			1
Banking and deposit interest expense [Member] | SMC embedded derivatives [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(4)	(2)
Banking and deposit interest expense [Member] | Derivatives not designated as hedging instruments [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	0	0	0
Banking and deposit interest expense [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	4	2
Distribution expenses [Member] | Derivatives not designated as hedging instruments [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	57	22	0
Distribution expenses [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	54	23	1
Distribution expenses [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	3	(1)	(1)
Interest credited to fixed accounts [Member] | IUL embedded derivatives [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(45)	15	(8)
Interest credited to fixed accounts [Member] | Indexed annuity embedded derivatives [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income			1
Interest credited to fixed accounts [Member] | Derivatives not designated as hedging instruments [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	30	35	(17)
Interest credited to fixed accounts [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	75	20	(10)
Benefits, Claims, Losses and Settlement Expenses [Member] | GMWB and GMAB embedded derivatives [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	663	237	(372)
Benefits, Claims, Losses and Settlement Expenses [Member] | Derivatives not designated as hedging instruments [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(464)	(624)	(450)
Benefits, Claims, Losses and Settlement Expenses [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	1	36	228
Benefits, Claims, Losses and Settlement Expenses [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(1,081)	(897)	(317)
Benefits, Claims, Losses and Settlement Expenses [Member] | Derivatives not designated as hedging instruments [Member] | Credit contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(22)	2	(1)
Benefits, Claims, Losses and Settlement Expenses [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(23)		13
Benefits, Claims, Losses and Settlement Expenses [Member] | Derivatives not designated as hedging instruments [Member] | Other contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	(2)	(2)	(1)
General and administrative expense [Member] | Derivatives not designated as hedging instruments [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	17	20	0
General and administrative expense [Member] | Derivatives not designated as hedging instruments [Member] | Equity contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	11	6	2
General and administrative expense [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange contracts [Member]
Summary of the impact of derivatives not designated as hedging instruments on the Consolidated Statements of Operations
Amount of gain (loss) on derivatives recognized in Income	$ 6	$ 14	$ (2)