Investments (Details Textuals 15) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment portfolio gains (losses)	$ 37	$ (153)
Non-investment portfolio gains (losses)	(151)	(7)	(6)
Goodwill Impairment Loss [Abstract]
Goodwill, Impairment Loss	1,868	0	0
Investments sold [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment portfolio gains (losses)	78	1
Impairments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment portfolio gains (losses)	(41)	(154)
Mitsui Sumitomo MetLife Insurance Co., LTD. ("MSI MetLife") [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-investment portfolio gains (losses)	0	0	209
Non-investment portfolio gain (loss) related to disposal of certain closed blocks of business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-investment portfolio gains (losses)	33	(106)
Goodwill Impairment Loss [Abstract]
Goodwill, Impairment Loss	$ 0	$ 65

The gain (loss) resulting from the sale of a disposal group that is not a discontinued operation. It is included in income from continuing operations before income taxes in the income statement.

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Loss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.

+ References

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