Discontinued and Held-for-sale Operations (Select Balance Sheet Information for Held-for-sale Operations) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other Assets	$ 7,390	$ 9,589
Total assets	148,452	151,167	166,199
Automotive finance operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other Assets	541	516
Total assets	$ 541	$ 516