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Derivative Financial Instruments - Schedule of Basis Swap (Details) - 1:3 basis swaps - USD ($)	3 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional amount	$ 7,150,000,000	$ 10,000,000,000
Net proceeds from termination of derivatives	500,000
2019
Derivative [Line Items]
Notional amount	0	3,500,000,000
2020
Derivative [Line Items]
Notional amount	1,000,000,000	1,000,000,000
2021
Derivative [Line Items]
Notional amount	250,000,000	250,000,000
2022
Derivative [Line Items]
Notional amount	2,000,000,000	2,000,000,000
Effective Start Date May 2020
Derivative [Line Items]
Notional amount	750,000,000
2023
Derivative [Line Items]
Notional amount	750,000,000	750,000,000
2024
Derivative [Line Items]
Notional amount	1,750,000,000	250,000,000
2026
Derivative [Line Items]
Notional amount	1,150,000,000	1,150,000,000
2027
Derivative [Line Items]
Notional amount	250,000,000	375,000,000
Notional amount, terminated	125,000,000
2028
Derivative [Line Items]
Notional amount	0	325,000,000
Notional amount, terminated	325,000,000
2029
Derivative [Line Items]
Notional amount	0	100,000,000
Notional amount, terminated	100,000,000
2031
Derivative [Line Items]
Notional amount	0	$ 300,000,000
Notional amount, terminated	$ 300,000,000

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Derivative, Notional Amount Terminated

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Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

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The net cash outflow or inflow for a financial contract that meets the hedge criteria as either cash flow hedge, fair value hedge or hedge of net investment in foreign operations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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