Acquisition of Businesses Contractually Required Payments Receivable (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Ally FInancial [Member]
Business Acquisition [Line Items]
Business Combination, Acquired Receivables, Fair Value	$ 15,144
Consumer Finance Receivables \| Ally FInancial [Member]
Business Acquisition [Line Items]
Business Combination, Acquired Receivables, Gross Contractual Amount	10,687
Business Combination, Acquired Receivables, Estimated Uncollectible	276
Business Combination, Acquired Receivables, Fair Value	9,709
Commercial Finance Receivables
Business Acquisition [Line Items]
Business Combination, Acquired Receivables, Fair Value	4,834
Commercial Finance Receivables \| Ally FInancial [Member]
Business Acquisition [Line Items]
Business Combination, Acquired Receivables, Gross Contractual Amount	4,947
Business Combination, Acquired Receivables, Estimated Uncollectible	27
Business Combination, Acquired Receivables, Fair Value	$ 4,834

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For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the best estimate at the acquisition date of the contractual cash flows not expected to be collected, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=6910749&loc=d3e4845-128472

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the fair value of the receivables acquired, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6910749&loc=d3e4845-128472

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the gross contractual amounts receivable, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=6910749&loc=d3e4845-128472

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant