Investments (Concentrations of Credit Risk - Narrative) (Details) (USD $) In Billions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 Foreign government debt securities [Member] Japan [Member]	Dec. 31, 2013 Foreign government debt securities [Member] Japan [Member]	Mar. 31, 2014 Fixed maturity and equity securities [Member] Japan [Member]	Dec. 31, 2013 Fixed maturity and equity securities [Member] Japan [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Securities holdings exposure in single issuer greater than stated percentage of Company's equity	10.00%
Government and agency fixed maturity securities		$ 22.0	$ 21.7	$ 27.2	$ 26.9