Statutory Financial Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statutory Accounting Practices [Line Items]
Dividends available to be paid	$ 3,800,000,000
Approximate increase in statutory capital and surplus resulting from discount of certain A&E liabilities	158,000,000
Statutory Accounting Practices, Statutory Capital and Surplus Required		13,700,000,000
PropertyAndCasualtySubsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	25,367,000,000	23,791,000,000
Statutory net income	3,368,000,000	3,333,000,000	2,683,000,000
LifeSubsidiaries [Member] [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	1,455,000,000	1,693,000,000
Statutory net income	$ (248,000,000)	$ 409,000,000	$ 199,000,000