Indemnity Earnings Per Share (Details) - Indemnity - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Class A
Income available to stockholders (Basic EPS:)
Allocated net income (numerator) (in dollars)	$ 56	$ 49	$ 94	$ 94
Weighted shares (denominator) (in shares)	46,189,068	46,214,153	46,189,068	46,307,659
Per-share amount (in dollars per share)	$ 1.21	$ 1.05	$ 2.04	$ 2.04
Dilutive effect of stock-based awards
Allocated net income (numerator) (in dollars)	$ 0	$ 0	$ 0	$ 0
Weighted shares (denominator) (in shares)	272,646	96,461	308,765	96,461
Assumed conversion of Class B shares
Allocated net income (numerator) (in dollars)	$ 0	$ 0	$ 1	$ 1
Weighted shares (denominator) (in shares)	6,100,800	6,100,800	6,100,800	6,100,800
Income available to stockholders on equivalent shares (Diluted EPS:)
Allocated net income (numerator) (in dollars)	$ 56	$ 49	$ 95	$ 95
Weighted shares (denominator) (in shares)	52,562,514	52,411,414	52,598,633	52,504,920
Per-share amount (in dollars per share)	$ 1.07	$ 0.94	$ 1.81	$ 1.82
Class B
Reconciliation of the numerators and denominators used in the basic and diluted per-share computations
Ratio for converting shares of Class B common stock into shares of Class A common stock (as a percent)	2400.00%		2400.00%		2400.00%
Income available to stockholders (Basic EPS:)
Allocated net income (numerator) (in dollars)	$ 0	$ 0	$ 1	$ 1
Weighted shares (denominator) (in shares)	2,542	2,542	2,542	2,542
Per-share amount (in dollars per share)	$ 181	$ 158	$ 306	$ 307
Income available to stockholders on equivalent shares (Diluted EPS:)
Allocated net income (numerator) (in dollars)	$ 0	$ 0	$ 1	$ 1
Weighted shares (denominator) (in shares)	2,542	2,542	2,542	2,542
Per-share amount (in dollars per share)	$ 180	$ 158	$ 305	$ 307