Investments (Consolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets:
Mortgage loans, at estimated fair value, relating to variable interest entities	$ 8,486	$ 9,157
Accrued investment income relating to variable interest entities	603	575
Liabilities
Long-term debt, at estimated fair value, relating to variable interest entities	2,759	3,350
Other liabilities relating to variable interest entities	6,238	6,547
Consolidated securitization entities [Member]
Assets:
Mortgage loans, at estimated fair value, relating to variable interest entities	2,096	2,666
Accrued investment income relating to variable interest entities	11	13
Total Assets	2,107	2,679
Liabilities
Long-term debt, at estimated fair value, relating to variable interest entities	1,969	2,559
Other liabilities relating to variable interest entities	10	13
Total Liabilities	$ 1,979	$ 2,572