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- Definition

The board of managers authorized additional debt securities for issuance

+ References

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- Definition

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

+ References

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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.

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Debt Notes and Debentures (Details) - USD ($) $ in Millions	Dec. 31, 2017	Mar. 31, 2017	May 31, 2016	Aug. 31, 2015	Mar. 31, 2015
Corporate Debt Securities \| Three Point Two Five Zero Percent Debentures Due June 15, 2027 [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount		$ 500
Debt instrument interest rate		3.25%
Corporate Debt Securities \| Four Point One Two Five Percent Debentures Due June 15, 2047 [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount		$ 750
Debt instrument interest rate		4.125%
Corporate Debt Securities \| Three Point Nine Zero Zero Percent Debentures Due August 1, 2046 [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount			$ 750
Debt instrument interest rate			3.90%
Corporate Debt Securities \| Three Point Six Five Zero Percent Debentures Due September 1, 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount				$ 350
Debt instrument interest rate				3.65%
Corporate Debt Securities \| Four Point Seven Zero Zero Percent Debentures Due September 1, 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount				$ 650
Debt instrument interest rate				4.70%
Corporate Debt Securities \| Three Point Zero Zero Zero Percent Debentures Due April 1, 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount					$ 500
Debt instrument interest rate					3.00%
Corporate Debt Securities \| Four Point One Five Zero Percent Debentures Due April 1, 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument issued amount					$ 1,000
Debt instrument interest rate					4.15%
SEC Debt Shelf Registration
Debt Instrument [Line Items]
The board of managers authorized additional debt securities for issuance	$ 1,500
Remaining amount of debt securities that may be issued	$ 1,750