Investments (Schedule of Securities Pledged by Contractual Maturity) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending	[1]	$ 136	$ 88
Total gross secured borrowings		286	240
Corporate Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements		150	152
Securities Lending		136	88
Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings		136	88
Overnight and Continuous [Member] | Corporate Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending		136	88
Greater than 90 days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total gross secured borrowings		150	152
Greater than 90 days [Member] | Corporate Bonds [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements		$ 150	$ 152

[1] Our pledged securities under securities lending agreements are included in fixed maturity AFS securities on our Consolidated Balance Sheets. We generally obtain collateral in an amount equal to 102% and 105% of the fair value of the domestic and foreign securities, respectively. We value collateral daily and obtain additional collateral when deemed appropriate. The cash received in our securities lending program is typically invested in cash and invested cash or fixed maturity AFS securities.