Finance Receivables (Allowance For Credit Losses And Finance Receivables By Portfolio Individually And Collectively Evaluated For Impairment) (Detail) (USD $)	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jul. 01, 2012	Apr. 01, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 0		$ 0	$ 0
Collectively evaluated for impairment	111,324,000		107,667,000	114,248,000
Total allowance for credit losses	111,324,000	106,792,000	107,667,000	114,248,000	122,503,000	125,449,000
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	6,336,910,000		5,889,519,000	6,130,817,000
Financing Receivable, Gross	6,336,910,000		5,889,519,000	6,130,817,000
Wholesale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	7,554,000		6,225,000	8,068,000
Total allowance for credit losses	7,554,000	8,250,000	6,225,000	8,068,000	9,646,000	9,337,000
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	1,088,621,000		816,404,000	905,038,000
Financing Receivable, Gross	1,088,621,000		816,404,000	905,038,000
Retail [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	103,770,000		101,442,000	106,180,000
Total allowance for credit losses	103,770,000	98,542,000	101,442,000	106,180,000	112,857,000	116,112,000
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	5,248,289,000		5,073,115,000	5,225,779,000
Financing Receivable, Gross	$ 5,248,289,000		$ 5,073,115,000	$ 5,225,779,000