Schedule VI. Supplemental Information Concerning Property and Casualty Insurance Operations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Incurred claim and claim adjustment expenses related to current year	$ 5,043	$ 5,114	$ 5,273
Incurred claim and claim adjustment expenses related to prior years	(36)	(115)	(182)
Consolidated Property and Casualty Insurance Entity [Member]
Deferred acquisition costs	600	624
Reserves for unpaid claim and claim adjustment expenses	23,271	24,015
Discount deducted from claim and claim adjustment expense reserves above (based on interest rates ranging from 3.5% to 8.0%)	1,578	1,586
Unearned Premiums	3,592	3,718
Net written premiums	7,088	7,348	6,964
Net earned premiums	7,212	7,271	6,881
Net investment income	2,031	2,240	2,074
Incurred claim and claim adjustment expenses related to current year	5,043	5,113	5,266
Incurred claim and claim adjustment expenses related to prior years	(39)	(115)	(180)
Amortization of deferred acquisition costs	1,317	1,362	1,274
Paid claim and claim adjustment expenses	$ 5,297	$ 5,566	$ 5,257
Supplemental Information Parenthetical
Minimum interest rate in discount range	3.50%
Maximum interest rate in discount range	8.00%