Derivative Instruments - Derivatives - Non-qualifying Strategies (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	$ 92	$ 15
Total other non-qualifying derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	10	0
Foreign Exchange Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	3	1
Interest rate swaps, swaptions, and futures
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	20	(8)
Credit derivatives that assume credit risk | Credit derivatives that purchase credit protection
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	6	1
Credit derivatives that assume credit risk | Credit derivatives that assume credit risk
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	(12)	21
Equity options
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Non-qualifying foreign currency derivatives	$ 75	$ 0