Derivatives - Fair Value Hedges - Non-qualifying Strategies (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	$ (24)	$ (12)	$ (6)
Interest rate swaps, swaptions and futures
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(35)	(3)	(5)
Credit derivatives | Credit derivatives that purchase credit protection
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(5)	0	28
Credit derivatives | Credit derivatives that assume credit risk
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	32	(14)	(7)
Equity index swaps and options
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(17)	2	(7)
Foreign Exchange Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	1	3	(14)
Contingent capital facility put option
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	$ 0	$ 0	$ (1)