Finance Receivables (Allowance For Credit Losses And Finance Receivables By Portfolio Individually And Collectively Evaluated For Impairment) (Detail) - USD ($)	Apr. 01, 2018	Dec. 31, 2017	Mar. 26, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 184,000	$ 0	$ 0
Collectively evaluated for impairment	190,166,000	192,471,000	184,030,000
Total allowance for credit losses	190,350,000	192,471,000	184,030,000	$ 173,343,000
Individually evaluated for impairment	220,000	0	0
Collectively evaluated for impairment	7,316,572,000	7,157,557,000	7,330,152,000
Financing receivable, gross	7,316,792,000	7,157,557,000	7,330,152,000
Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	182,150,000	186,254,000	176,068,000
Total allowance for credit losses	182,150,000	186,254,000	176,068,000	166,810,000
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	6,064,192,000	6,140,600,000	6,002,550,000
Financing receivable, gross	6,064,192,000	6,140,600,000	6,002,550,000
Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	184,000	0	0
Collectively evaluated for impairment	8,016,000	6,217,000	7,962,000
Total allowance for credit losses	8,200,000	6,217,000	7,962,000	$ 6,533,000
Individually evaluated for impairment	220,000	0	0
Collectively evaluated for impairment	1,252,380,000	1,016,957,000	1,327,602,000
Financing receivable, gross	$ 1,252,600,000	$ 1,016,957,000	$ 1,327,602,000