Debt - Debt With A Contractual Term Greater Than One Year (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jul. 01, 2018
Debt Instrument
Gross long-term debt	$ 7,046,364	$ 6,463,466	$ 5,813,809
Less: current portion of long-term debt, net of unamortized discount and debt issuance costs	(2,396,188)	(1,575,799)	(945,463)
Long-term debt, net	4,650,176	4,887,667	4,868,346
Secured Debt
Debt Instrument
Less: unamortized discount and debt issuance costs	(3,541)	(49)	(202)
Gross long-term debt	1,615,745	833,835	636,068
Secured Debt \| Asset-backed Canadian commercial paper conduit facility
Debt Instrument
Long-term debt, gross	148,740	155,951	166,638
Secured Debt \| Asset-backed U.S. commercial paper conduit facilities
Debt Instrument
Long-term debt, gross	464,136	582,717	300,000
Secured Debt \| Asset-backed securitization debt
Debt Instrument
Long-term debt, gross	1,006,410	95,216	169,632
Medium-term notes
Debt Instrument
Long-term debt, gross	4,687,660	4,887,007	4,435,449
Less: unamortized discount and debt issuance costs	$ (12,340)	(12,993)	(14,551)
Medium-term notes \| Due in 2019, issued January 2016
Debt Instrument
Debt instrument, stated percentage	2.25%
Long-term debt, gross	$ 0	600,000	600,000
Medium-term notes \| Due in 2019, issued March 2017
Debt Instrument
Long-term debt, gross	$ 0	150,000	150,000
Medium-term notes \| Due in 2019, issued September 2014
Debt Instrument
Debt instrument, stated percentage	2.40%
Long-term debt, gross	$ 600,000	600,000	600,000
Medium-term notes \| Due in 2020, issued February 2015
Debt Instrument
Debt instrument, stated percentage	2.15%
Long-term debt, gross	$ 600,000	600,000	600,000
Medium-term notes \| Due in 2020, issued May 2018
Debt Instrument
Long-term debt, gross	$ 450,000	450,000	450,000
Medium-term notes \| Due in 2020, issued March 2017
Debt Instrument
Debt instrument, stated percentage	2.40%
Long-term debt, gross	$ 350,000	350,000	350,000
Medium-term notes \| Due in 2021, issued January 2016
Debt Instrument
Debt instrument, stated percentage	2.85%
Long-term debt, gross	$ 600,000	600,000	600,000
Medium-term notes \| Due in 2021, issued November 2018
Debt Instrument
Long-term debt, gross	$ 450,000	450,000	0
Medium-term notes \| Due in 2021, issued May 2018
Debt Instrument
Debt instrument, stated percentage	3.55%
Long-term debt, gross	$ 350,000	350,000	350,000
Medium-term notes \| Due in 2022, issued February 2019
Debt Instrument
Debt instrument, stated percentage	4.05%
Long-term debt, gross	$ 550,000	0	0
Medium-term notes \| Due in 2022, issued June 2017
Debt Instrument
Debt instrument, stated percentage	2.55%
Long-term debt, gross	$ 400,000	400,000	400,000
Medium-term notes \| Due in 2023, issued February 2018
Debt Instrument
Debt instrument, stated percentage	3.35%
Long-term debt, gross	$ 350,000	350,000	350,000
Senior notes
Debt Instrument
Less: unamortized discount and debt issuance costs	(7,041)	(7,376)	(7,708)
Gross long-term debt	$ 742,959	742,624	742,292
Senior notes \| Due in 2025, issued July 2015
Debt Instrument
Debt instrument, stated percentage	3.50%
Long-term debt, gross	$ 450,000	450,000	450,000
Senior notes \| Due in 2045, issued July 2015
Debt Instrument
Debt instrument, stated percentage	4.625%
Long-term debt, gross	$ 300,000	300,000	300,000
Unsecured Debt
Debt Instrument
Gross long-term debt	$ 5,430,619	$ 5,629,631	$ 5,177,741
Unsecured Debt \| Due in 2019, issued March 2017
Debt Instrument
Debt instrument, stated percentage	0.35%
Unsecured Debt \| Due in 2020, issued May 2018
Debt Instrument
Debt instrument, stated percentage	0.50%
Unsecured Debt \| Due in 2021, issued November 2018
Debt Instrument
Debt instrument, stated percentage	0.94%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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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

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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