Offsetting Assets and Liabilities Offsetting Assets and Liabilities (Tables)

3 Months Ended

Mar. 31, 2013

Offsetting Assets and Liabilities [Abstract]

Offsetting Assets and Liabilities [Table Text Block]

The composition of offsetting derivative instruments, financial assets, and financial liabilities was as follows.

									Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet
March 31, 2013 ($ in millions)	Gross Amounts of Recognized Assets/(Liabilities)			Gross Amounts Offset in the Condensed Consolidated Balance Sheet		Net Amounts of Assets/(Liabilities) Presented in the Condensed Consolidated Balance Sheet			Financial Instruments			Collateral (a)			Net Amount
Assets
Derivative assets in net asset positions	$	545		$	—	$	545		$	(34	)	$	(469	)	$	42
Derivative assets in net liability positions	37			—		37			(37		)	—			—
Derivative assets with no offsetting arrangements	86			—		86			—			—			86
Total assets	$	668		$	—	$	668		$	(71	)	$	(469	)	$	128
Liabilities
Derivative liabilities in net liability positions	$	(362	)	$	—	$	(362	)	$	37		$	304		$	(21	)
Derivative liabilities in net asset positions	(34		)	—		(34		)	34			—			—
Derivative liabilities with no offsetting arrangements	(10		)	—		(10		)	—			—			(10		)
Total liabilities	$	(406	)	$	—	$	(406	)	$	71		$	304		$	(31	)

(a) Financial collateral received/pledged shown as a balance based on the sum of all net asset and liability positions between Ally and each individual derivative counterparty.

									Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet
December 31, 2012 ($ in millions)	Gross Amounts of Recognized Assets/(Liabilities)			Gross Amounts Offset in the Condensed Consolidated Balance Sheet		Net Amounts of Assets/(Liabilities) Presented in the Condensed Consolidated Balance Sheet			Financial Instruments			Collateral (a)			Net Amount
Assets
Derivative assets in net asset positions	$	1,395		$	—	$	1,395		$	(503	)	$	(841	)	$	51
Derivative assets in net liability positions	788			—		788			(788		)	—			—
Derivative assets with no offsetting arrangements	115			—		115			—			—			115
Total assets	$	2,298		$	—	$	2,298		$	(1,291	)	$	(841	)	$	166
Liabilities
Derivative liabilities in net liability positions	$	(1,929	)	$	—	$	(1,929	)	$	788		$	1,092		$	(49	)
Derivative liabilities in net asset positions	(503		)	—		(503		)	503			—			—
Derivative liabilities with no offsetting arrangements	(36		)	—		(36		)	—			—			(36		)
Total liabilities	$	(2,468	)	$	—	$	(2,468	)	$	1,291		$	1,092		$	(85	)

(a) Financial collateral received/pledged shown as a balance based on the sum of all net asset and liability positions between Ally and each individual derivative counterparty.