Finance Receivables - Aging Analysis (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number Of Days After Which Finance Receivable Is Considered Past Due	any payment, including principal and interest, that is at least 31 days past the contractual due date
Number Of Days At Which Finance Receivables Are In Process Of Collection	90 days
Finance Receivables Aging Analysis [Abstract]
Financing Receivables	$ 97,196	$ 87,236
Consumer Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	16	17
Finance Receivables Aging Analysis [Abstract]
Total past due	881	896
Current	59,068	53,200
Financing Receivables	59,949	54,096
Non-Consumer Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	1	3
Finance Receivables Aging Analysis [Abstract]
Total past due	116	117
Current	37,131	33,023
Financing Receivables	37,247	33,140
31-60 Days Past Due [Member] | Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	708	718
61-90 Days Past Due [Member] | Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	108	97
91-120 Days Past Due [Member] | Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	27	29
Greater Than 120 Days Past Due [Member] | Consumer Segment [Member]
Finance Receivables Aging Analysis [Abstract]
Total past due	$ 38	$ 52