Investments (Securities Lending and Repurchase Agreements Remaining Tenor ) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	$ 12,092	$ 21,055
U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	10,494	20,007
Foreign government
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	1,344	1,047
Agency RMBS
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	254	0
U.S. corporate
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	1
Open (1)
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	1,945	5,901
Open (1) | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	1,945	5,900
Open (1) | Foreign government
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Open (1) | Agency RMBS
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Open (1) | U.S. corporate
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	1
1 Month or Less
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	5,933	7,337
1 Month or Less | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	5,448	7,052
1 Month or Less | Foreign government
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	422	285
1 Month or Less | Agency RMBS
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	63	0
1 Month or Less | U.S. corporate
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Over 1 Month to 6 Months
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	4,214	7,817
Over 1 Month to 6 Months | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	3,101	7,055
Over 1 Month to 6 Months | Foreign government
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	922	762
Over 1 Month to 6 Months | Agency RMBS
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	191	0
Over 1 Month to 6 Months | U.S. corporate
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Over 6 Months to 1 Year
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Over 6 Months to 1 Year | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Over 6 Months to 1 Year | Foreign government
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Over 6 Months to 1 Year | Agency RMBS
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Over 6 Months to 1 Year | U.S. corporate
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Repurchase Agreements
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	3,125	3,325
Repurchase Agreements | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	3,125	3,325
Repurchase Agreements | Open (1) | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Repurchase Agreements | 1 Month or Less | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	3,125	3,325
Repurchase Agreements | Over 1 Month to 6 Months | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	0	0
Repurchase Agreements | Over 6 Months to 1 Year | U.S. government and agency
Securities Financing Transaction [Line Items]
Cash collateral on deposit from counterparties	$ 0	$ 0