Indemnity Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Changes in Indemnity's accumulated other comprehensive income (loss) by component attributable to the Indemnity shareholder interest
Other comprehensive income	$ 50	$ 72	$ 0
Indemnity
Changes in Indemnity's accumulated other comprehensive income (loss) by component attributable to the Indemnity shareholder interest
Balance, beginning of period	(118)	(59)	(59)
Other comprehensive income before reclassifications, net of tax	0	4
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	(1)
Other comprehensive income	0	3	(59)
Balance, end of period	(118)	(56)	(118)
Indemnity | Unrealized holding gains (losses) on available-for-sale securities
Changes in Indemnity's accumulated other comprehensive income (loss) by component attributable to the Indemnity shareholder interest
Balance, beginning of period	7	6	6
Other comprehensive income before reclassifications, net of tax	0	4
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	(1)
Other comprehensive income	0	3
Balance, end of period	7	9
Indemnity | Postretirement plans
Changes in Indemnity's accumulated other comprehensive income (loss) by component attributable to the Indemnity shareholder interest
Balance, beginning of period	(125)	(65)	(65)
Other comprehensive income before reclassifications, net of tax	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	0
Other comprehensive income	0	0
Balance, end of period	$ (125)	$ (65)