Finance Receivables, Net (Summary of Impaired Loans by Class of Finance Receivable) (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017
Impaired Finance Receivables
Impaired Finance Receivables Individually Evaluated with Related Allowance	$ 265		$ 218
Impaired Finance Receivables Individually Evaluated with No Related Allowance	229		239
Impaired Finance Receivables Aggregated And Evaluated For Impairment	225		220
Impaired Finance Receivables	719		677
Unpaid Principal Balance
Unpaid Principal Balance Individually Evaluated with Related Allowance	265		218
Unpaid Principal Balance Individually Evaluated with No Related Allowance	229		239
Unpaid Principal Balance Aggregated And Evaluated For Impairment	222		217
Unpaid Principal Balance	716		674
Individually Evaluated Allowance	47		33
Average Impaired Finance Receivables
Average Impaired Finance Receivables Individually Evaluated For Impairment with An Allowance	242	$ 209
Average Impaired Finance Receivables Individually Evaluated For Impairment Without An Allowance	234	294
Average Impaired Finance Receivables Account Balances Aggregated And Evaluated For Impairment	222	226
Average Impaired Finance Receivables	698	729
Interest Income Recognized
Interest Income Recognized Individually Evaluated with Related Allowance	2	1
Interest Income Recognized Individually Evaluated with No Related Allowance	2	3
Interest Income Recognized Aggregated And Evaluated For Impairment	4	4
Interest Income Recognized	8	8
Wholesale [Member]
Impaired Finance Receivables
Impaired Finance Receivables Individually Evaluated with Related Allowance	126		93
Impaired Finance Receivables Individually Evaluated with No Related Allowance	134		134
Impaired Finance Receivables	260		227
Unpaid Principal Balance
Unpaid Principal Balance Individually Evaluated with Related Allowance	126		93
Unpaid Principal Balance Individually Evaluated with No Related Allowance	134		134
Unpaid Principal Balance	260		227
Individually Evaluated Allowance	12		12
Average Impaired Finance Receivables
Average Impaired Finance Receivables Individually Evaluated For Impairment with An Allowance	109	69
Average Impaired Finance Receivables Individually Evaluated For Impairment Without An Allowance	134	189
Average Impaired Finance Receivables	243	258
Interest Income Recognized
Interest Income Recognized Individually Evaluated with Related Allowance	1	0
Interest Income Recognized Individually Evaluated with No Related Allowance	1	2
Interest Income Recognized	2	2
Real estate [Member]
Impaired Finance Receivables
Impaired Finance Receivables Individually Evaluated with Related Allowance	93		94
Impaired Finance Receivables Individually Evaluated with No Related Allowance	95		105
Impaired Finance Receivables	188		199
Unpaid Principal Balance
Unpaid Principal Balance Individually Evaluated with Related Allowance	93		94
Unpaid Principal Balance Individually Evaluated with No Related Allowance	95		105
Unpaid Principal Balance	188		199
Individually Evaluated Allowance	12		12
Average Impaired Finance Receivables
Average Impaired Finance Receivables Individually Evaluated For Impairment with An Allowance	94	105
Average Impaired Finance Receivables Individually Evaluated For Impairment Without An Allowance	100	103
Average Impaired Finance Receivables	194	208
Interest Income Recognized
Interest Income Recognized Individually Evaluated with Related Allowance	1	1
Interest Income Recognized Individually Evaluated with No Related Allowance	1	1
Interest Income Recognized	2	2
Working capital [Member]
Impaired Finance Receivables
Impaired Finance Receivables Individually Evaluated with Related Allowance	46		31
Impaired Finance Receivables Individually Evaluated with No Related Allowance	0		0
Impaired Finance Receivables	46		31
Unpaid Principal Balance
Unpaid Principal Balance Individually Evaluated with Related Allowance	46		31
Unpaid Principal Balance Individually Evaluated with No Related Allowance	0		0
Unpaid Principal Balance	46		31
Individually Evaluated Allowance	23		9
Average Impaired Finance Receivables
Average Impaired Finance Receivables Individually Evaluated For Impairment with An Allowance	39	35
Average Impaired Finance Receivables Individually Evaluated For Impairment Without An Allowance	0	2
Average Impaired Finance Receivables	39	37
Interest Income Recognized
Interest Income Recognized Individually Evaluated with Related Allowance	0	0
Interest Income Recognized Individually Evaluated with No Related Allowance	0	0
Interest Income Recognized	0	0
Retail Loan [Member]
Impaired Finance Receivables
Impaired Finance Receivables Aggregated And Evaluated For Impairment	225		220
Impaired Finance Receivables	225		220
Unpaid Principal Balance
Unpaid Principal Balance Aggregated And Evaluated For Impairment	222		217
Unpaid Principal Balance	222		$ 217
Average Impaired Finance Receivables
Average Impaired Finance Receivables Account Balances Aggregated And Evaluated For Impairment	222	226
Average Impaired Finance Receivables	222	226
Interest Income Recognized
Interest Income Recognized Aggregated And Evaluated For Impairment	4	4
Interest Income Recognized	$ 4	$ 4

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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