Investments (Net Investment Gains Losses - Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from foreign currency transactions		$ 1,000,000	$ 2,000,000
Maximum
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from foreign currency transactions	132,000,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	26,000,000	128,000,000	192,000,000
Debt Securities [Member] | Other Other Than Temporary Investment Losses [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	$ 0	$ 13,000,000	$ 67,000,000