Investments (Details) - Fixed Maturities - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investment disclosure details
Fixed maturities, amortized cost	$ 74,751	$ 68,830
Allowance for expected credit losses	3	2
Gross unrealized gains	3,356	5,186
Gross unrealized losses	294	11
Fixed maturities, at fair value	77,810	74,003
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Investment disclosure details
Fixed maturities, amortized cost	3,574	2,111
Allowance for expected credit losses	0	0
Gross unrealized gains	20	38
Gross unrealized losses	32	0
Fixed maturities, at fair value	3,562	2,149
Obligations of states, municipalities and political subdivisions [Member]
Investment disclosure details
Fixed maturities, amortized cost	34,925	33,763
Allowance for expected credit losses	0	0
Gross unrealized gains	2,012	2,599
Gross unrealized losses	75	2
Fixed maturities, at fair value	36,862	36,360
Obligations of states, municipalities and political subdivisions, local general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	18,668	17,289
Allowance for expected credit losses	0	0
Gross unrealized gains	1,045	1,370
Gross unrealized losses	46	2
Fixed maturities, at fair value	19,667	18,657
Obligations of states, municipalities and political subdivisions, revenue [Member]
Investment disclosure details
Fixed maturities, amortized cost	11,274	11,806
Allowance for expected credit losses	0	0
Gross unrealized gains	693	909
Gross unrealized losses	27	0
Fixed maturities, at fair value	11,940	12,715
Obligations of states, municipalities and political subdivisions, state general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,158	1,343
Allowance for expected credit losses	0	0
Gross unrealized gains	67	101
Gross unrealized losses	2	0
Fixed maturities, at fair value	1,223	1,444
Obligations of states, municipalities and political subdivisions, pre-refunded [Member]
Investment disclosure details
Fixed maturities, amortized cost	3,825	3,325
Allowance for expected credit losses	0	0
Gross unrealized gains	207	219
Gross unrealized losses	0	0
Fixed maturities, at fair value	4,032	3,544
Debt securities issued by foreign governments [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,041	1,028
Allowance for expected credit losses	0	0
Gross unrealized gains	7	26
Gross unrealized losses	7	0
Fixed maturities, at fair value	1,041	1,054
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,754	2,222
Allowance for expected credit losses	0	0
Gross unrealized gains	68	139
Gross unrealized losses	5	0
Fixed maturities, at fair value	1,817	2,361
All other corporate bonds [Member]
Investment disclosure details
Fixed maturities, amortized cost	33,445	29,683
Allowance for expected credit losses	3	2	$ 0
Gross unrealized gains	1,247	2,382
Gross unrealized losses	175	9
Fixed maturities, at fair value	34,514	32,054
Redeemable preferred stock [Member]
Investment disclosure details
Fixed maturities, amortized cost	12	23
Allowance for expected credit losses	0	0
Gross unrealized gains	2	2
Gross unrealized losses	0	0
Fixed maturities, at fair value	$ 14	$ 25

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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