Variable Interest Entities Variable Interest Entity - Change in Fair Value of Assets and Liabilities (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Deconsolidated VIE Assets	$ 1,233								$ 1,233
Fixed income securities, amortized cost	3,187				$ 3,451				3,187	$ 3,451
Long-term debt	2,822				2,929				2,822	2,929
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	132				133				132	133
Loans, Unpaid principal balance					19					19	$ 19
Variable Interest Entity Change in Fair Value of Assets and Liabilities									13	3	20
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax											0
Realized Investment Gains (Losses)	9	$ 18	$ 36	$ 17	29	$ 30	$ 47	$ 5	81	112	5
Variable Interest Entity, Initial Consolidation, Gain (Loss)									15	0	0
Variable Interest Entities Deconsolidation Gain Loss									(2)	2	0
Variable Interest Entity, Measure of Activity, Income or Loss before Tax									38	3	20
Variable Interest Entity, Consolidated, Carrying Amount, Assets	292								292
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	364								364
Deconsolidated VIE Liabilities	1,230								1,230
Variable Interest Entity, Primary Beneficiary [Member]
Long-term debt	4,554				5,269				4,554	5,269
Interest Expense, Long-term Debt									(11)	0	0
Other Expenses									(1)	0	0
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member]
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax									0	(1)
Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Loans, Unpaid principal balance	2,618				3,418				2,618	3,418
Long-term debt, Unpaid principal balance	$ 3,800				$ 4,553				3,800	4,553
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax									14	2	20
Available-for-sale Securities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Gross Investment Income, Operating									10	0	0
Realized Investment Gains (Losses)									$ 13	$ 0	$ 0
Consolidated Entities [Member]
Number of DeConsolidated Variable Interest Entities									1	4	1