CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues
Premiums earned									$ 4,214	$ 3,987	$ 3,869
Net investment income									433	433	433
Net realized investment (losses) gains									(4)	313	412
Net impairment losses recognized in earnings									(2)	(6)	(126)
Equity in earnings (losses) of limited partnerships									149	128	(369)
Other income									34	35	36
Total revenues	1,418	796	1,245	1,365	1,401	1,357	916	1,216	4,824	4,890	4,255
Benefits and expenses
Insurance losses and loss expenses									3,444	2,900	2,728
Policy acquisition and underwriting expenses									1,022	969	1,003
Goodwill impairment										22
Total benefits and expenses	993	1,101	1,419	953	984	952	967	988	4,466	3,891	3,731
Income (loss) from operations before income taxes and noncontrolling interests	425	(305)	(174)	412	417	405	(51)	228	358	999	524
Provision for income taxes									90	339	78
Net income	281	(180)	(107)	274	254	275	(31)	162	268	660	446
Less: Net income attributable to noncontrolling interest in consolidated entity - Exchange	255	(227)	(159)	230	242	221	(80)	115	99	498	338
Net income attributable to Indemnity	26	47	52	44	12	54	49	47	169	162	108
Indemnity
Revenues
Net investment income									16	37	42
Net realized investment (losses) gains									3	(1)	10
Benefits and expenses
Income (loss) from operations before income taxes and noncontrolling interests									256	269	154
Provision for income taxes									85	104	49
Net income									$ 169	$ 162	$ 108
Class A | Indemnity
Net income attributable to Indemnity per share
Common stock - basic (in dollars per share)	$ 0.55	$ 0.97	$ 1.05	$ 0.88	$ 0.25	$ 1.05	$ 0.96	$ 0.92	$ 3.45	$ 3.18	$ 2.10
Common stock - diluted (in dollars per share)	$ 0.49	$ 0.87	$ 0.94	$ 0.78	$ 0.22	$ 0.94	$ 0.86	$ 0.82	$ 3.08	$ 2.85	$ 1.89
Weighted average shares outstanding attributable to Indemnity - Basic
Common stock - basic (in shares)									48,875,316	50,705,607	51,250,606
Weighted average shares outstanding attributable to Indemnity - Diluted
Common stock - diluted (in shares)									55,057,437	56,884,894	57,428,999
Class B | Indemnity
Net income attributable to Indemnity per share
Common stock - basic (in dollars per share)	$ 81.76	$ 146.67	$ 158.33	$ 126.48	$ 40.93	$ 150.87	$ 138.21	$ 132.83	$ 522.47	$ 462.83	$ 312.45
Common stock - diluted (in dollars per share)	$ 81.76	$ 146.67	$ 158.33	$ 126.48	$ 40.93	$ 150.87	$ 138.21	$ 132.83	$ 522.47	$ 462.83	$ 312.45
Weighted average shares outstanding attributable to Indemnity - Basic
Common stock - basic (in shares)									2,546	2,546	2,549
Weighted average shares outstanding attributable to Indemnity - Diluted
Common stock - diluted (in shares)									2,546	2,546	2,549