Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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Year when the debt instrument is scheduled to be fully repaid.

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The net gain (loss) recognized in earnings during the reporting period representing the amount of ineffectiveness for cash flow hedges.

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The amount of gain or loss recognized in AOCI related to the settlement of forward-starting interest rate swaps.

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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=34725769&loc=d3e28878-108400

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-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

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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.

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No definition available.

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Date the derivative contract matures, in CCYY-MM-DD format.

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- Definition

Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

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- Definition

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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Financial Instruments, Summary of forward-starting and fixed-for-floating interest rate swaps (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Feb. 28, 2015	Jan. 31, 2015
Senior Notes due 2019 [Member]
Derivative [Line Items]
Maturity year				2019		2019
Face amount		$ 2,000		$ 2,000		$ 2,000
Stated interest rate (in hundredths)		5.00%		5.00%		5.00%
Senior Notes due 2055 [Member]
Derivative [Line Items]
Maturity year				2055
Face amount		$ 1,000		$ 1,000
Stated interest rate (in hundredths)		4.625%		4.625%
Guaranteed Notes due 2044 [Member]
Derivative [Line Items]
Maturity year				2044		2044
Face amount		$ 1,000		$ 1,000		$ 1,000
Stated interest rate (in hundredths)		4.875%		4.875%		4.875%
Interest rate swaps [Member] \| Forward-starting interest rate swaps [Member]
Derivative [Line Items]
Gain (loss) recognized in AOCI related to settlement of swaps				$ 15		$ (17)
Pre-tax deferred gains (losses) scheduled to be reclassified from AOCI to interest expense over the next twelve months		$ 1		$ 1
Interest rate swaps [Member] \| Forward-starting interest rate swaps [Member] \| Senior Notes due 2019 [Member] \| Forward-starting interest rate swaps entered into in March 2015 [Member]
Derivative [Line Items]
Maturity year				2019
Notional amounts value		$ 1,000		$ 1,000
Gain (loss) recognized related to the ineffectiveness of cash flow hedging relationships		less than $1 million		less than $1 million
Interest rate swaps [Member] \| Forward-starting interest rate swaps [Member] \| Senior Notes due 2055 [Member] \| Forward-starting interest rate swaps entered into in January 2015 [Member]
Derivative [Line Items]
Maturity year	2055
Notional amounts value								$ 750
Gain (loss) recognized related to the ineffectiveness of cash flow hedging relationships				less than $1 million
Face amount	$ 1,000
Interest rate swaps [Member] \| Forward-starting interest rate swaps [Member] \| Guaranteed Notes due 2044 [Member] \| Forward-starting interest rate swaps entered into in February 2014 [Member]
Derivative [Line Items]
Maturity year				2044
Notional amounts value							$ 500
Face amount		$ 1,000		$ 1,000
Interest rate swaps [Member] \| Fixed-for-floating interest rate swaps [Member]
Derivative [Line Items]
Notional amounts value		2,000		2,000
Gain (loss) recognized related to the ineffectiveness of fair value hedging relationships		$ 10	$ 6	$ 32	$ 6
Derivative, maturity date				Apr. 15, 2019
Interest rate swaps [Member] \| Fixed-for-floating interest rate swaps [Member] \| Senior Notes due 2019 [Member]
Derivative [Line Items]
Maturity year						2019
Notional amounts value						$ 2,000
Stated interest rate (in hundredths)						5.00%