CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Revenues
Premiums earned	$ 1,175	$ 1,087
Net investment income	103	108
Net realized investment gains	249	296
Net impairment losses recognized in earnings	0	0
Equity in earnings of limited partnerships	36	21
Other income	8	8
Total revenues	1,571	1,520
Benefits and expenses
Insurance losses and loss expenses	842	716
Policy acquisition and underwriting expenses	293	270
Total benefits and expenses	1,135	986
Income (loss) from operations before income taxes and noncontrolling interest	436	534
Provision for income taxes	146	180
Net income (loss)	290	354	619
Less: Net income attributable to noncontrolling interest in consolidated entity – Exchange	253	318
Net income attributable to Indemnity	37	36
Indemnity
Revenues
Net investment income	4	4
Net realized investment gains	0	3
Net impairment losses recognized in earnings	0	0
Benefits and expenses
Income (loss) from operations before income taxes and noncontrolling interest	56	54
Net income (loss)	37		160
Net income attributable to Indemnity	$ 37	$ 36
Class A | Indemnity
Net income attributable to Indemnity per share
Common stock - basic (in dollars per share)	$ 0.78	$ 0.76
Common stock - diluted (in dollars per share)	$ 0.69	$ 0.67
Weighted average shares outstanding attributable to Indemnity - Basic
Common stock - basic (in shares)	46,774,968	47,749,799
Weighted average shares outstanding attributable to Indemnity - Diluted
Common stock - diluted (in shares)	52,960,165	53,930,044
Dividends declared per share
Common stock (in dollars per share)	$ 0.5925	$ 0.5525	$ 4.25
Class B | Indemnity
Net income attributable to Indemnity per share
Common stock - basic (in dollars per share)	$ 117.00	$ 114.00
Common stock - diluted (in dollars per share)	$ 117.00	$ 114.00
Weighted average shares outstanding attributable to Indemnity - Basic
Common stock - basic (in shares)	2,542	2,545
Weighted average shares outstanding attributable to Indemnity - Diluted
Common stock - diluted (in shares)	2,542	2,545
Dividends declared per share
Common stock (in dollars per share)	$ 88.8750	$ 82.8750	$ 637.5000