Consolidated Balance Sheet Parentheticals (Unaudited at March 31, 2021) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 70,286	$ 68,830
Fixed maturities, available for sale, allowance for expected credit losses	2	2
Equity securities, cost	387	387
Premiums receivable, allowance for expected credit losses	110	105
Reinsurance recoverables, allowance for estimated uncollectible reinsurance	142	146
Contractholder receivables, allowance for expected credit losses	$ 19	$ 19
Common stock, shares authorized (in shares)	1,750.0	1,750.0
Common stock, shares issued (in shares)	251.5	252.4
Common stock, shares outstanding (in shares)	251.5	252.4
Treasury stock, at cost (in shares)	530.0	527.3