Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	$ 254	$ 24
Undistributed Earnings of Foreign Subsidiaries	115
Deferred Tax Assets, Valuation Allowance	104
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	104	28	27
Income Tax Examination, Penalties and Interest Expense	(7)	5	3
Income Tax Examination, Penalties Accrued	149	37
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	44
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	51
Deposit To Reduce Unrecognized Tax Benefit Liabilities	44
Difference Between Amounts Paid Under Tax Sharing Arrangement and for Financial Reporting Purposes	1
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Deferred Tax Assets, Valuation Allowance	28
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Deferred Tax Assets, Valuation Allowance	76
Ally Financial International Operations [Member] | Foreign Tax Authority [Member]
Income Taxes [Line Items]
Deferred Tax Assets, Valuation Allowance	73
Subsidiaries [Member]
Income Taxes [Line Items]
Related Party Tax Expense, Due to Affiliates, Deferred	15
Expiring in 2034 [Member]
Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	76
Expiring Indefinitely [Member]
Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	$ 177