Indemnity Shareholders' Equity and Noncontrolling Interest (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Reconciliation of the beginning and ending balances of Indemnity's shareholders' equity and the noncontrolling interest
Balance, beginning of period			$ 7,550	$ 6,791	$ 6,791
Net income	108	267	320	734	1,048
Change in other comprehensive income (loss), net of tax	(63)	(2)	74	(221)	(144)
Net purchase of treasury stock			(19)		(32)
Dividends declared:
Balance, end of period	7,836		7,836		7,550
Class A
Dividends declared:
Dividends declared			(88)		(112)
Class B
Dividends declared:
Dividends declared			(1)		(1)
Indemnity
Reconciliation of the beginning and ending balances of Indemnity's shareholders' equity and the noncontrolling interest
Balance, beginning of period			734	642	642
Net income			142		163
Change in other comprehensive income (loss), net of tax			3		74
Net purchase of treasury stock			(19)		(32)
Dividends declared:
Balance, end of period	771		771		734
Indemnity | Class A
Dividends declared:
Dividends declared (in dollars per share)	$ 0.6350	$ 0.5925	$ 1.9050	$ 1.7775	$ 2.4125
Dividends declared			(88)		(112)
Indemnity | Class B
Dividends declared:
Dividends declared (in dollars per share)	$ 95.2500	$ 88.8750	$ 285.7500	$ 266.6250	$ 361.8750
Dividends declared			(1)		(1)
Exchange
Reconciliation of the beginning and ending balances of Indemnity's shareholders' equity and the noncontrolling interest
Balance, beginning of period			6,816	6,149	6,149
Net income			178		885
Change in other comprehensive income (loss), net of tax			71		(218)
Dividends declared:
Balance, end of period	$ 7,065		$ 7,065		$ 6,816