CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Cash and cash equivalents	$ 240	$ 185
Other assets	510	441
Indemnity
Fixed maturities, amortized cost	495	535
Equity securities, cost	24	24
Trading securities, cost	24	23
Limited partnerships, cost	179	185
Cash and cash equivalents	13	11
Other assets	115	119
Treasury stock (in shares)	21,010,834	20,427,758
Exchange
Fixed maturities, amortized cost	6,995	6,829
Equity securities, cost	546	531
Trading securities, cost	2,050	2,021
Limited partnerships, cost	1,003	1,003
Cash and cash equivalents	227	174
Other assets	$ 395	$ 322
Class A | Indemnity
Common stock, stated value per share (in dollars per share)	$ 0.0292	$ 0.0292
Common stock, authorized (in shares)	74,996,930	74,996,930
Common stock, issued (in shares)	68,294,400	68,289,600
Common stock, outstanding (in shares)	47,283,566	47,861,842
Class B | Indemnity
Ratio for converting shares of Class B common stock into shares of Class A common stock (as a percent)	2400.00%	2400.00%
Common stock, stated value per share (in dollars per share)	$ 70	$ 70
Common stock, authorized (in shares)	2,544	2,546
Common stock, issued (in shares)	2,544	2,546
Common stock, outstanding (in shares)	2,544	2,546