Notes Payable - Callable Medium-Term Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
2023	$ 3,004,203	$ 3,696,699
2024	2,809,551	1,592,315
2025	927,119	1,202,817
Total principal net of discounts	$ 21,795,677	$ 19,091,215
Weighted - average rate (as a percent)	1.37%	2.28%
2022
Debt Instrument [Line Items]
2022	$ 2,123,372
Weighted - average rate (as a percent)	1.34%
2023
Debt Instrument [Line Items]
2023	$ 2,390,730
Weighted - average rate (as a percent)	1.39%
2024
Debt Instrument [Line Items]
2024	$ 884,138
Weighted - average rate (as a percent)	1.74%
2025
Debt Instrument [Line Items]
2025	$ 1,126,871
Weighted - average rate (as a percent)	1.15%
Thereafter
Debt Instrument [Line Items]
Thereafter	$ 2,464,572
Weighted - average rate (as a percent)	2.19%
Call Option
Debt Instrument [Line Items]
2022	$ 243,410
2023	592,529
2024	119,898
2025	306,683
Thereafter	670,657
Total principal net of discounts	$ 1,933,177
Weighted - average rate (as a percent)	1.15%
Call Option \| 2022
Debt Instrument [Line Items]
Weighted - average rate (as a percent)	0.42%
Call Option \| 2023
Debt Instrument [Line Items]
Weighted - average rate (as a percent)	0.97%
Call Option \| 2024
Debt Instrument [Line Items]
Weighted - average rate (as a percent)	1.56%
Call Option \| 2025
Debt Instrument [Line Items]
Weighted - average rate (as a percent)	1.08%
Call Option \| Thereafter
Debt Instrument [Line Items]
Weighted - average rate (as a percent)	1.51%

Long-Term Debt, Maturity, after Year Four

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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, 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
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-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
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-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

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