Investments (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Investment Income:
Investment income, before expense	$ 4,149	$ 4,221	$ 4,154
Investment expense	(206)	(211)	(183)
Net investment income	3,943	4,010	3,971
Fixed income securities
Net Investment Income:
Investment income, before expense	2,921	3,234	3,484
Equity securities
Net Investment Income:
Investment income, before expense	149	127	122
Mortgage loans
Net Investment Income:
Investment income, before expense	372	374	359
Limited partnership interests
Net Investment Income:
Investment income, before expense	541	348	88
Short-term investments
Net Investment Income:
Investment income, before expense	5	6	6
Other
Net Investment Income:
Investment income, before expense	$ 161	$ 132	$ 95