Allowance for Credit Losses and Recorded Investment in Finance Receivables by Portfolio Segment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2014
Allowance for Credit Losses for Finance Receivables:
Allowance for credit losses at	$ 447	$ 501	$ 454	$ 527
Provision for credit losses	79	28	117	39
Allowance for credit losses at	445	467	445	467
Gross Finance Receivables:
Finance receivables	66,160		66,160		65,774
Finance Receivables, Net [Member]
Allowance for Credit Losses for Finance Receivables:
Allowance for credit losses at	381	424	386	445
Charge-offs	(77)	(67)	(129)	(117)
Recoveries	15	16	31	35
Provision for credit losses	62	23	93	33
Allowance for credit losses at	381	396	381	396
Ending Balance: Individually Evaluated for Impairment	26	33	26	33
Ending Balance: Collectively Evaluated for Impairment	355	363	355	363
Gross Finance Receivables:
Finance receivables	66,160	64,843	66,160	64,843	65,774
Ending Balance: Individually Evaluated for Impairment	206	220	206	220
Ending Balance: Collectively Evaluated for Impairment	65,954	64,623	65,954	64,623
Finance Receivables, Net [Member] | Retail Loan [Member]
Allowance for Credit Losses for Finance Receivables:
Allowance for credit losses at	291	309	296	333
Charge-offs	(76)	(67)	(128)	(116)
Recoveries	15	16	31	35
Provision for credit losses	69	32	100	38
Allowance for credit losses at	299	290	299	290
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	299	290	299	290
Gross Finance Receivables:
Finance receivables	50,726	49,591	50,726	49,591
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	50,726	49,591	50,726	49,591
Gross Finance Receivables	292	366	292	366
Finance Receivables, Net [Member] | Commercial [Member]
Allowance for Credit Losses for Finance Receivables:
Allowance for credit losses at	2	3	2	5
Charge-offs	(1)	0	(1)	(1)
Recoveries	0	0	0	0
Provision for credit losses	0	1	0	0
Allowance for credit losses at	1	4	1	4
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	1	4	1	4
Gross Finance Receivables:
Finance receivables	481	395	481	395
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	481	395	481	395
Gross Finance Receivables	1	1	1	1
Finance Receivables, Net [Member] | Dealer Products [Member]
Allowance for Credit Losses for Finance Receivables:
Allowance for credit losses at	88	112	88	107
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	(7)	(10)	(7)	(5)
Allowance for credit losses at	81	102	81	102
Ending Balance: Individually Evaluated for Impairment	26	33	26	33
Ending Balance: Collectively Evaluated for Impairment	55	69	55	69
Gross Finance Receivables:
Finance receivables	14,953	14,857	14,953	14,857
Ending Balance: Individually Evaluated for Impairment	206	220	206	220
Ending Balance: Collectively Evaluated for Impairment	14,747	14,637	14,747	14,637
Finance Receivables, Net [Member] | Dealer Products [Member] | TMS [Member] | Financial Guarantee [Member]
Gross Finance Receivables:
Ending Balance: Collectively Evaluated for Impairment	866	830	866	830
Finance Receivables, Net [Member] | Dealer Products [Member] | Private Toyota Distributors [Member] | Financial Guarantee [Member]
Gross Finance Receivables:
Ending Balance: Collectively Evaluated for Impairment	152	149	152	149
Investments In Operating Leases, Net [Member]
Allowance for Credit Losses for Finance Receivables:
Allowance for credit losses at					68
Allowance for credit losses at	$ 64		$ 64		$ 68