Variable Interest Entities ("VIE's") (Consolidated Variable Interest Entity Asset and Liability Information) (Details) $ in Millions		Jun. 30, 2017 USD ($) item	Dec. 31, 2016 USD ($) item
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments, Assets | item		1	2
Notional Amounts, Assets		$ 542	$ 733
Carrying Value, Assets			$ 200
Total Return Swap [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments, Assets | item		1	1
Notional Amounts, Assets		$ 542	$ 533
Carrying Value, Assets
Credit default swaps [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments, Assets | item			1
Notional Amounts, Assets			$ 200
Carrying Value, Assets
Fixed maturity securities [Member] | Asset-backed credit card loans [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments, Assets | item	[1]
Notional Amounts, Assets	[1]
Carrying Value, Assets	[1]		$ 200

[1] Reported in variable interest entities' fixed maturity securities on our Consolidated Balance Sheets.