Finance Receivables (Allowance For Credit Losses And Finance Receivables By Portfolio Individually And Collectively Evaluated For Impairment) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jul. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses
Individually evaluated for impairment	$ 0		$ 0	$ 0
Collectively evaluated for impairment	193,447		192,471	195,582
Total allowance for credit losses	193,447	$ 193,930	192,471	195,582	$ 193,528	$ 173,343
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	7,497,009		7,157,557	7,296,607
Financing receivable, gross	7,497,009		7,157,557	7,296,607
Retail
Financing Receivable, Allowance for Credit Losses
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	187,126		186,254	189,664
Total allowance for credit losses	187,126	187,502	186,254	189,664	185,899	166,810
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	6,508,670		6,140,600	6,336,447
Financing receivable, gross	6,508,670		6,140,600	6,336,447
Wholesale
Financing Receivable, Allowance for Credit Losses
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	6,321		6,217	5,918
Total allowance for credit losses	6,321	$ 6,428	6,217	5,918	$ 7,629	$ 6,533
Individually evaluated for impairment	0		0	0
Collectively evaluated for impairment	988,339		1,016,957	960,160
Financing receivable, gross	$ 988,339		$ 1,016,957	$ 960,160

A valuation allowance for financing receivables that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(3))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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