Derivative Financial Instruments and Off-balance sheet Financial Instruments - Foreign currency contracts in cash flow hedging and other (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) contract	Dec. 31, 2018 USD ($) contract	Dec. 31, 2017 USD ($) contract
Derivative Instruments, Gain (Loss)
Derivative, number of instruments held | contract	6,592	7,062
Total gain (loss) recognized in net income on derivatives	$ 19	$ 45	$ 33
Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Total gain (loss) recognized in net income on derivatives	11	7	(16)
Contract benefits
Derivative Instruments, Gain (Loss)
Total gain (loss) recognized in net income on derivatives	7	(5)	9
Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Total gain (loss) recognized in net income on derivatives	1	43	40
Interest rate contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		1
Interest rate contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		1
Interest rate contracts | Contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		0
Interest rate contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		0
Equity and index contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	63	(27)	41
Equity and index contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	5	(4)	(4)
Equity and index contracts | Contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0	0
Equity and index contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	58	(23)	45
Embedded derivative financial instruments
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(50)	61	4
Embedded derivative financial instruments | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0	0
Embedded derivative financial instruments | Contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	7	(5)	9
Embedded derivative financial instruments | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(57)	66	(5)
Foreign currency contracts
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in OCI on derivatives during the period	0	1	(2)
Gain recognized in OCI on derivatives during the term of the hedging relationship	0	0	2
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	3	12	(14)
Foreign currency contracts | Net investment income
Derivative Instruments, Gain (Loss)
Investment income, net	0	0	1
Foreign currency contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Investment income, net	0	3	0
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	3	12	(14)
Foreign currency contracts | Contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0	0
Foreign currency contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0	0
Credit default contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(1)		2
Credit default contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(1)		2
Credit default contracts | Contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0		0
Credit default contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0		$ 0
Total return swaps - fixed income
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	1	(1)
Total return swaps - fixed income | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	1	(1)
Total return swaps - fixed income | Life and Annuity Contract Benefits [Member]
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0
Total return swaps - fixed income | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0
Total return swaps - equity index
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	3	(1)
Total return swaps - equity index | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	3	(1)
Total return swaps - equity index | Contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	0	0
Total return swaps - equity index | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	$ 0	$ 0
Fair Value Hedging | Derivatives designated as accounting hedging instruments
Derivative Instruments, Gain (Loss)
Derivative, number of instruments held | contract	1	0	0
Cash Flow Hedging | Derivatives designated as accounting hedging instruments
Derivative Instruments, Gain (Loss)
Derivative, number of instruments held | contract	0	1	1