Derivatives - Fair Value Hedges - Non-qualifying Strategies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Foreign Currency Swaps and Forwards [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	$ 17	$ 17
Total other non-qualifying derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(5)
Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	34	(48)
Not Designated as Hedging Instrument | Fair Value Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	22	(68)
Not Designated as Hedging Instrument | GMWB Product Derivatives [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	39	101
Not Designated as Hedging Instrument | GMWB Reinsurance [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(13)	(18)
Not Designated as Hedging Instrument | GMWB Hedging Instruments [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(22)	(65)
Not Designated as Hedging Instrument | Macro Hedge Program [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	18	(86)
Not Designated as Hedging Instrument | Foreign Currency Swaps and Forwards [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(3)	(4)
Not Designated as Hedging Instrument | Fixed Annuity Hedging Instruments [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	20	21
Not Designated as Hedging Instrument | Foreign Exchange Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	17	17
Not Designated as Hedging Instrument | Interest rate swaps, swaptions and futures
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(30)	2
Not Designated as Hedging Instrument | Credit Risk Contract [Member] | Credit derivatives that purchase credit protection
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	0	(6)
Not Designated as Hedging Instrument | Credit Risk Contract [Member] | Credit derivatives that assume credit risk
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(1)	8
Not Designated as Hedging Instrument | Equity index options
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	0	1
Not Designated as Hedging Instrument | Other Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	$ 26	(2)
Not Designated as Hedging Instrument | Total other non-qualifying derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives		$ 3