Investments (Consolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Total Assets	$ 6,309	$ 6,323
Total Liabilities	2,212	2,169
Consolidated Securitization Entities [Member]
Variable Interest Entity [Line Items]
Total Assets	282	297
Total Liabilities	136	155
MRSC collateral financing arrangement [Member]
Variable Interest Entity [Line Items]
Total Assets	3,469	3,471
Total Liabilities	0	0
Operating joint venture [Member]
Variable Interest Entity [Line Items]
Total Assets	2,466	2,405
Total Liabilities	2,076	1,999
Other limited partnership interests
Variable Interest Entity [Line Items]
Total Assets	34	37
Total Liabilities	0	0
Real estate joint ventures
Variable Interest Entity [Line Items]
Total Assets	0	9
Total Liabilities	0	15
Other invested assets
Variable Interest Entity [Line Items]
Total Assets	58	59
Total Liabilities	0	0
FVO and trading securities
Variable Interest Entity [Line Items]
Total Assets	0	45
Total Liabilities	$ 0	$ 0