Investments (Net Investment Gains Losses - Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment portfolio gains (losses)		$ (35)		$ 60
Non-investment portfolio gains (losses)	27	(10)	34	(35)
Gains (losses) from foreign currency transactions	17	25	75	83
Investments sold [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment portfolio gains (losses)		(27)		75
Impairments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment portfolio gains (losses)		(8)		(15)
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)	$ 0		$ 30