Investments (Details Textuals 15) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other investment portfolio gains (losses)	$ (35)		$ 60
Other investment portfolio gains (losses)	(46)	(35)	(11)	(87)
Securities and mortgage loans [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other investment portfolio gains (losses)	(27)		75
Impairments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other investment portfolio gains (losses)	(8)		(15)
Mitsui Sumitomo MetLife Insurance Co., LTD. ("MSI MetLife") [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other investment portfolio gains (losses)		$ (7)		$ (87)