Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

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Balance Type:	credit
Period Type:	instant

- 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.

+ Details

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Aggregate amount of interest paid or due on all long-term debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.8)
-URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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Debt and Credit Facilities - Senior Unsecured Notes (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Feb. 29, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2017
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 3,000
Debt Instrument, Redemption Price, Percentage		100.00%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		101.00%
Interest Expense, Long-term Debt		$ 1,000	$ 1,100	$ 1,000
Senior Unsecured Note Issued September 2017 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Repayments of Unsecured Debt		2,250	750
Senior Unsecured Note Issued September 2014 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Repayments of Unsecured Debt		$ 500
Senior Unsecured Note Issued September 2015 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Repayments of Unsecured Debt			$ 1,000
Subsequent Event [Member] \| Senior Unsecured Note Issued September 2014 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Repayments of Unsecured Debt	$ 500