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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Topic 835
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-Section 45
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
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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

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
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- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.8)
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- Definition

The cash outflow for a long-term debt where the holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Debt and Credit Facility - Senior Unsecured Notes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017
2017 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 3,000,000,000.0
2017 Senior Unsecured Notes Due in September 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				750,000,000
2017 Senior Unsecured Notes Due in September 2019 with Floating Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				500,000,000
2017 Senior Unsecured Notes Due in September 2019 with Fixed Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 1,000,000,000.0
Debt Instrument, Interest Rate, Stated Percentage	1.85%			1.85%
2016 Senior Unsecured Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 5,000,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	101.00%
Interest Expense, Long-term Debt	$ 1,000,000,000	907,000,000	$ 605,000,000
2011 Senior Unsecured Notes
Debt Instrument [Line Items]
Repayments of Unsecured Debt		$ 700,000,000