Debt And Commitments - Public Unsecured Debt Securities (Details) (Automotive [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Debentures due August 1, 2018 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	6.50%
Debentures due January 15, 2022 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	8.875%
Debentures due October 3, 2022 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	6.55%
Debentures due November 15, 2025 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.125%
Debentures due August 1, 2026 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.50%
Debentures due February 15, 2028 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	6.625%
Debentures due October 1, 2028 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	6.625%
Debentures due February 1, 2029 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	6.375%
Debentures due September 3, 2029 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	5.95%
Debentures due June 3, 2030 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	6.15%
GLOBLS due July 16, 2031 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.45%
Debentures due January 15, 2032 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	8.90%
Debentures due February 15, 2032 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	9.95%
Debentures due April 2, 2035 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	5.75%
Debentures due June 10, 2043 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.50%
Debentures due June 15, 2043 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.75%
Debentures due November 1, 2046 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.40%
Debentures due February 15, 2047 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	9.98%
Debentures due May 15, 2097 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	7.70%
Debentures due September 15, 2021 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - coupon rate	9.215%
Public unsecured debt - on lent	$ 180
Public Unsecured Debt Securities [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	5,260	5,260
Public Unsecured Debt Securities [Member] | Debentures due August 1, 2018 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	361	361
Public Unsecured Debt Securities [Member] | Debentures due January 15, 2022 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	86	86
Public Unsecured Debt Securities [Member] | Debentures due October 3, 2022 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	15	15
Public Unsecured Debt Securities [Member] | Debentures due November 15, 2025 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	209	209
Public Unsecured Debt Securities [Member] | Debentures due August 1, 2026 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	193	193
Public Unsecured Debt Securities [Member] | Debentures due February 15, 2028 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	104	104
Public Unsecured Debt Securities [Member] | Debentures due October 1, 2028 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	638	638
Public Unsecured Debt Securities [Member] | Debentures due February 1, 2029 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	260	260
Public Unsecured Debt Securities [Member] | Debentures due September 3, 2029 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	8	8
Public Unsecured Debt Securities [Member] | Debentures due June 3, 2030 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	10	10
Public Unsecured Debt Securities [Member] | GLOBLS due July 16, 2031 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	1,794	1,794
Public Unsecured Debt Securities [Member] | Debentures due January 15, 2032 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	151	151
Public Unsecured Debt Securities [Member] | Debentures due February 15, 2032 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	4	4
Public Unsecured Debt Securities [Member] | Debentures due April 2, 2035 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	40	40
Public Unsecured Debt Securities [Member] | Debentures due June 10, 2043 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	593	593
Public Unsecured Debt Securities [Member] | Debentures due June 15, 2043 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	73	73
Public Unsecured Debt Securities [Member] | Debentures due November 1, 2046 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	398	398
Public Unsecured Debt Securities [Member] | Debentures due February 15, 2047 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	181	181
Public Unsecured Debt Securities [Member] | Debentures due May 15, 2097 [Member]
Public Unsecured Debt Securities Table and footnote [Abstract]
Public unsecured debt - principal outstanding	$ 142	$ 142