Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
DAC and VOBA	$ 1,510	$ 2,226
Future Policy Benefits and Contract Owner Account Balances	52,625	50,876
Unearned Premiums	0	(1)
Net Investment Income	2,909	2,792	$ 2,669
Premiums and Fee Income	4,442	4,242	4,114
Interest Credited and Other Benefits to Contract Owners	4,101	3,750	3,537
Amortization of DAC and VOBA	352	182	232
Other Operating Expenses	2,654	2,753	2,599
Premiums Written (Excluding Life)	1,510	1,361	1,187
Retirement
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
DAC and VOBA	207	667
Future Policy Benefits and Contract Owner Account Balances	35,818	34,008
Unearned Premiums	0	0
Net Investment Income	2,213	2,029	1,971
Premiums and Fee Income	921	881	879
Interest Credited and Other Benefits to Contract Owners	1,101	1,067	908
Amortization of DAC and VOBA	211	79	116
Other Operating Expenses	1,421	1,371	1,284
Premiums Written (Excluding Life)	0	0	0
Investment Management
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
DAC and VOBA	0	0
Future Policy Benefits and Contract Owner Account Balances	0	0
Unearned Premiums	0	0
Net Investment Income	8	12	(27)
Premiums and Fee Income	659	641	663
Interest Credited and Other Benefits to Contract Owners	0	0	0
Amortization of DAC and VOBA	5	4	3
Other Operating Expenses	584	573	547
Premiums Written (Excluding Life)	0	0	0
Employee Benefits
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
DAC and VOBA	135	117
Future Policy Benefits and Contract Owner Account Balances	2,183	2,141
Unearned Premiums	0	(1)
Net Investment Income	115	112	113
Premiums and Fee Income	2,047	1,920	1,741
Interest Credited and Other Benefits to Contract Owners	1,487	1,408	1,322
Amortization of DAC and VOBA	20	16	17
Other Operating Expenses	443	410	354
Premiums Written (Excluding Life)	1,510	1,361	1,187
Corporate
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
DAC and VOBA	1,168	1,442
Future Policy Benefits and Contract Owner Account Balances	14,624	14,727
Unearned Premiums	0	0
Net Investment Income	573	639	612
Premiums and Fee Income	815	800	831
Interest Credited and Other Benefits to Contract Owners	1,513	1,275	1,307
Amortization of DAC and VOBA	116	83	96
Other Operating Expenses	206	399	414
Premiums Written (Excluding Life)	$ 0	$ 0	$ 0