Indemnity Capital Stock (Details) (Indemnity, USD $)	12 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Long-term incentive plan Employees	Jul. 31, 2011 Class A	Dec. 31, 2012 Class A	Jun. 30, 2012 Class A Long-term incentive plan	Jan. 31, 2012 Class A Long-term incentive plan	Jul. 31, 2011 Class A Long-term incentive plan	Jul. 31, 2011 Class A Other stock-based awards	Oct. 31, 2011 Class A Stock repurchases Stock repurchase program	Dec. 31, 2012 Class A Stock repurchases Stock repurchase program	Dec. 31, 2011 Class A Stock repurchases Stock repurchase program	Dec. 31, 2012 Class B	Dec. 31, 2011 Class B
Class of Stock [Line Items]
Minimum multiplier for dividend payable on Class A common stock per dividend declared on Class B common stock (as a percent)	67.00%
Percentage of dividend declared on Class B common stock used to determine dividend payable on Class A common stock (as a percent)	67.00%
Ratio for converting shares of Class B common stock into shares of Class A common stock (as a percent)												2400.00%	2400.00%
Class B common stock shares converted into Class A common stock shares (in shares)												4
Class A common stock shares issued upon conversion of Class B common stock shares (in shares)				9,600
Stock Repurchases
Shares repurchased (in shares)										1,000,000	2,200,000
Total cost of shares repurchased										$ 69,000,000	$ 155,000,000
Amount of authorized stock repurchase approved for continuation									150,000,000
Approximate amount of repurchase authority remaining under stock repurchase program										68,000,000
Shares repurchased outside of publicly announced program for share based compensation awards (in shares)			64,095	1,803	1,134	669	57,695	6,400
Total plan awards paid, share based			$ 4,800,000	$ 129,849	$ 79,125	$ 50,724	$ 4,300,000	$ 500,000
Average share price (in dollars per share)					$ 69.78	$ 75.82	$ 73.72	$ 73.74
Number of retired senior vice presidents		2