Finance Receivables (Narrative) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Greater Than 90 Days Past Due [Member]	Dec. 31, 2012 Greater Than 90 Days Past Due [Member]	Apr. 01, 2012 Greater Than 90 Days Past Due [Member]	Mar. 31, 2013 Retail [Member]	Dec. 31, 2012 Retail [Member]	Apr. 01, 2012 Retail [Member]	Dec. 31, 2011 Retail [Member]	Mar. 31, 2013 Retail [Member] Greater Than 90 Days Past Due [Member]	Dec. 31, 2012 Retail [Member] Greater Than 90 Days Past Due [Member]	Apr. 01, 2012 Retail [Member] Greater Than 90 Days Past Due [Member]	Mar. 31, 2013 Wholesale [Member]	Dec. 31, 2012 Wholesale [Member]	Apr. 01, 2012 Wholesale [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance Receivables That Are Individually Deemed To Be Impaired												$ 0	$ 0	$ 0
Allowance for credit losses					98,542,000	101,442,000	112,857,000	116,112,000
Retail financing receivables, gross					4,981,488,000	5,073,115,000	5,043,584,000		20,258,000	27,597,000	16,262,000
Financing Receivable, Recorded Investment, Nonaccrual Status												0	0	0
Wholesale finance receivables, gross		$ 800,000	$ 400,000	$ 300,000
FICO score for determining credit risk	640