Investments (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Gain (Loss) on Securities [Line Items]
Debt securities, available-for-sale, accrued interest, after allowance for credit loss	$ 387,000,000	$ 390,000,000	$ 387,000,000	$ 390,000,000	$ 371,000,000
Mortgage loan losses due to changes in expected credit losses	0	3,000,000	0	16,000,000
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments	2,481,000,000		2,481,000,000		2,773,000,000
Notional value	272,000,000		272,000,000		190,000,000
Derivative liability, fair value, gross liability	(11,000,000)		(11,000,000)		$ (19,000,000)
Commitments to purchase or fund privately placed debt securities	1,250,000,000		1,250,000,000
Commitments to sell various privately placed debt securities	55,000,000		55,000,000
5.750%, face amount of $400, due August 15, 2021 | Senior Notes
Gain (Loss) on Securities [Line Items]
Equity securities, FV-NI, gain (loss)		(20,000,000)		(20,000,000)
Face amount	400,000,000		400,000,000
Common Stock
Gain (Loss) on Securities [Line Items]
Equity securities, FV-NI, gain (loss)	(7,000,000)	4,000,000	11,000,000	9,000,000
Non-redeemable preferred stock
Gain (Loss) on Securities [Line Items]
Equity securities, FV-NI, gain (loss)	(2,000,000)	$ 25,000,000	15,000,000	$ (44,000,000)
Mortgage loans
Gain (Loss) on Securities [Line Items]
Financing receivable, accrued interest, after allowance for credit loss	$ 4,000,000		$ 4,000,000