Investments (Consolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Total Assets	$ 6,451	$ 6,323
Total Liabilities	2,300	2,169
Consolidated Securitization Entities [Member]
Variable Interest Entity [Line Items]
Total Assets	288	297
Total Liabilities	147	155
MRSC collateral financing arrangement [Member]
Variable Interest Entity [Line Items]
Total Assets	3,458	3,471
Total Liabilities	0	0
Operating joint venture [Member]
Variable Interest Entity [Line Items]
Total Assets	2,544	2,405
Total Liabilities	2,123	1,999
Other limited partnership interests
Variable Interest Entity [Line Items]
Total Assets	37	37
Total Liabilities	0	0
Mortgage loans
Variable Interest Entity [Line Items]
Total Assets	9	9
Total Liabilities	15	15
Other invested assets
Variable Interest Entity [Line Items]
Total Assets	73	59
Total Liabilities	15	0
FVO and trading securities
Variable Interest Entity [Line Items]
Total Assets	42	45
Total Liabilities	$ 0	$ 0