Related Party Transactions (Financing Support) (Details) In Millions, unless otherwise specified	Mar. 31, 2013 USD ($)	Mar. 31, 2012 USD ($)	Mar. 31, 2013 BTB [Member] USD ($)	Mar. 31, 2012 BTB [Member] USD ($)	Mar. 31, 2013 TFA [Member] USD ($)	Mar. 31, 2012 TFA [Member] USD ($)	Mar. 31, 2013 TFSA [Member] USD ($)	Mar. 31, 2012 TFSA [Member] USD ($)	Mar. 31, 2013 TMFNL [Member] USD ($)	Mar. 31, 2013 TMFNL [Member] EUR (€)	Mar. 31, 2012 TMFNL [Member] USD ($)	Mar. 31, 2013 TCCI [Member] USD ($)	Mar. 31, 2013 TCCI [Member] CAD	Mar. 31, 2012 TCCI [Member] USD ($)	Mar. 31, 2013 TFSB [Member] USD ($)	Mar. 31, 2012 TFSB [Member] USD ($)	Mar. 31, 2013 TFSMX [Member] USD ($)	Mar. 31, 2012 TFSMX [Member] USD ($)
Related Party Transaction [Line Items]
Financing available to TMCC					$ 1,000		$ 200			€ 1,000			1,500
Amounts oustanding provided by parent and affiliates	48	61			0	0	48	61	0		0	0		0
Amounts outstanding provided to affiliates	931	1,052	127	121	350	550	0	0	419		381	0		0	35	0	0	0
Financing made available by TMCC			$ 300		$ 1,000		$ 200			€ 1,000			2,500		$ 400		$ 500