Investments (Schedule of Securities Pledged by Contractual Maturity) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending	$ 300	$ 116
Total gross secured borrowings	300	116
Corporate Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings	299	114
Foreign Government Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings	1	2
Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings	300	116
Overnight and Continuous [Member] | Corporate Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings	299	114
Overnight and Continuous [Member] | Foreign Government Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings	$ 1	$ 2