Investments (Details) - Investment Information, Debt Securities - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Investment disclosure details
Fixed maturities, amortized cost	$ 76,471			$ 74,751
Allowance for expected credit losses	3			3
Gross unrealized gains	56			3,356
Gross unrealized losses	8,074			294
Fixed maturities, at fair value	68,450			77,810
Proceeds from sales of fixed maturities classified as available for sale	3,951	$ 2,864
Gross realized gains	17	56
Gross realized losses	52	5
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Investment disclosure details
Fixed maturities, amortized cost	4,453			3,574
Allowance for expected credit losses	0			0
Gross unrealized gains	0			20
Gross unrealized losses	419			32
Fixed maturities, at fair value	4,034			3,562
Obligations of U.S. states, municipalities and political subdivisions [Member]
Investment disclosure details
Fixed maturities, amortized cost	35,148			34,925
Allowance for expected credit losses	0			0
Gross unrealized gains	23			2,012
Gross unrealized losses	4,043			75
Fixed maturities, at fair value	31,128			36,862
Obligations of U.S. states, municipalities and political subdivisions, local general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	19,851			18,668
Allowance for expected credit losses	0			0
Gross unrealized gains	5			1,045
Gross unrealized losses	2,644			46
Fixed maturities, at fair value	17,212			19,667
Obligations of U.S. states, municipalities and political subdivisions, revenue [Member]
Investment disclosure details
Fixed maturities, amortized cost	11,066			11,274
Allowance for expected credit losses	0			0
Gross unrealized gains	7			693
Gross unrealized losses	1,265			27
Fixed maturities, at fair value	9,808			11,940
Obligations of U.S. states, municipalities and political subdivisions, state general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,131			1,158
Allowance for expected credit losses	0			0
Gross unrealized gains	1			67
Gross unrealized losses	128			2
Fixed maturities, at fair value	1,004			1,223
Obligations of U.S. states, municipalities and political subdivisions, pre-refunded [Member]
Investment disclosure details
Fixed maturities, amortized cost	3,100			3,825
Allowance for expected credit losses	0			0
Gross unrealized gains	10			207
Gross unrealized losses	6			0
Fixed maturities, at fair value	3,104			4,032
Debt securities issued by foreign governments [Member]
Investment disclosure details
Fixed maturities, amortized cost	995			1,041
Allowance for expected credit losses	0			0
Gross unrealized gains	1			7
Gross unrealized losses	55			7
Fixed maturities, at fair value	941			1,041
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Investment disclosure details
Fixed maturities, amortized cost	2,020			1,754
Allowance for expected credit losses	0			0
Gross unrealized gains	10			68
Gross unrealized losses	210			5
Fixed maturities, at fair value	1,820			1,817
Corporate and all other bonds [Member]
Investment disclosure details
Fixed maturities, amortized cost	33,855			33,457
Allowance for expected credit losses	3	$ 2	$ 4	3	$ 2	$ 2
Gross unrealized gains	22			1,249
Gross unrealized losses	3,347			175
Fixed maturities, at fair value	$ 30,527			$ 34,528