Fair Value (Instruments Not Measured at Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Carrying Amount
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Long-term receivables	$ 387	$ 432
Non-recourse debt	15,373	15,535
Recourse debt	6,187	6,485
Fair Value
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Long-term receivables	304	414
Non-recourse debt	16,000	15,862
Recourse debt	6,899	6,640
Fair Value | Level 1
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Long-term receivables	0
Non-recourse debt	0
Recourse debt	0
Fair Value | Level 2
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Long-term receivables	0
Non-recourse debt	12,156
Recourse debt	6,899
Fair Value | Level 3
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Long-term receivables	304
Non-recourse debt	3,844
Recourse debt	$ 0