Fair Value Measurements Changes in Fair Value Level 3 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Investment Segment [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, [Roll Forward]
Balance at January 1	$ 289	$ 329
Gross realized and unrealized gains	4	8
Gross proceeds	(5)	(48)
Balance at December 31	288	289
Holding Company [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, [Roll Forward]
Balance at January 1	0	0
Gross realized and unrealized gains	0	0
Transfer in	81	0
Balance at December 31	81	0
Fair Value, Inputs, Level 3 [Member] | Recurring measurement [Member] | Railcar and Food Packaging [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, [Roll Forward]
Balance at January 1	27	28
Realized/unrealized gains (losses), net	3	(1)
Purchases and settlements, net	0	0
Balance at December 31	30	27
Fair Value, Inputs, Level 3 [Member] | United States Plans | Recurring measurement [Member] | Automotive Segment [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, [Roll Forward]
Balance at January 1	0	0
Realized/unrealized gains (losses), net	2	0
Purchases and settlements, net	12	0
Balance at December 31	14	0
Fair Value, Inputs, Level 3 [Member] | Non-U.S. Plans | Recurring measurement [Member] | Automotive Segment [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, [Roll Forward]
Balance at January 1	35	33
FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetForeignExchangeMovements	1	(1)
Realized/unrealized gains (losses), net	1	2
Purchases and settlements, net	7	4
Gross proceeds	(2)	(3)
Balance at December 31	$ 42	$ 35