Indemnity Accumulated Other Comprehensive Income (Loss) (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Amounts reclassified out of accumulated other comprehensive income (loss) and the related affected line item in the Consolidated Statements of Operations where net income is presented
Net realized investment gains (losses)	$ 191	$ 169	$ 501	$ 358
Net impairment losses recognized in earnings	(9)	0	(10)	0
Income (loss) from operations before income taxes and noncontrolling interest	398	270	1,097	734
Provision for income taxes	131	86	363	234
Net income (loss)	267	184	734	500	619
Less: Net loss attributable to noncontrolling interest in consolidated entity – Exchange	221	133	607	370
Net income attributable to Indemnity	46	51	127	130
Amounts reclassified from accumulated other comprehensive income (loss)
Amounts reclassified out of accumulated other comprehensive income (loss) and the related affected line item in the Consolidated Statements of Operations where net income is presented
Net income attributable to Indemnity	1		1
Unrealized holding gains (losses) on available-for-sale securities | Amounts reclassified from accumulated other comprehensive income (loss)
Amounts reclassified out of accumulated other comprehensive income (loss) and the related affected line item in the Consolidated Statements of Operations where net income is presented
Net realized investment gains (losses)	(24)		(3)
Net impairment losses recognized in earnings	(9)		(10)
Income (loss) from operations before income taxes and noncontrolling interest	(33)		(13)
Provision for income taxes	(12)		(5)
Net income (loss)	(21)		(8)
Less: Net loss attributable to noncontrolling interest in consolidated entity – Exchange	(22)		(9)
Net income attributable to Indemnity	1		1
Amortization of postretirement plan items | Amounts reclassified from accumulated other comprehensive income (loss)
Amounts reclassified out of accumulated other comprehensive income (loss) and the related affected line item in the Consolidated Statements of Operations where net income is presented
Net income attributable to Indemnity	$ 0		$ 0