Increase in percentage points added to the reference rate to compute the variable rate on the debt instrument.

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- Definition

Debt Instrument, Incremental Decrease in Basis Spread on Variable Rate Resulting from Upgrades

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No definition available.

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- Definition

Debt Instrument, Incremental Increase in Basis Spread on Variable Rate Resulting from Downgrades

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No definition available.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM format.

+ References

No definition available.

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- Definition

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

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-Paragraph 1
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- 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.

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- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

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No definition available.

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- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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- Definition

The cash outflow for a borrowing having initial term of repayment within one year or the normal operating cycle, if longer.

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Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

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Debt (Senior Notes - Narrative) (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Jul. 31, 2016	Jan. 31, 2015	Dec. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Aug. 30, 2018	Jul. 31, 2018	Dec. 31, 2016
Debt Instrument [Line Items]
Loss on early extinguishment of debt	$ 59				$ 59	$ 10	$ 11	$ 8	$ 70
Payment of premiums	53
Repayments of long-term debt								$ 1,191	1,139
Repayment of short-term debt									287
Consideration											$ 1,865
Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt	1,100		$ 2,200
Increase in basis spread		1.75%
Senior Notes [Member] \| Over LIBOR [Member]
Debt Instrument [Line Items]
Incremental increase in basis points resulting from downgrades			0.25%
Incremental decrease in basis points resulting from upgrades			0.25%
Increase in basis spread		1.75%
3.30% Senior Notes due January 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes			$ 350
Stated interest rate			3.30%
Maturity date, year and month			2018-01
Repayments of long-term debt							$ 38
4.05% Senior Notes due January 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes			$ 850
Stated interest rate		5.80%	4.05%					4.05%		4.05%		5.30%
Maturity date, year and month			2020-01					2020-01		2020-01
Repayments of long-term debt	758
4.95% Senior Notes due January 2025 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes			$ 1,000
Stated interest rate		6.70%	4.95%					4.95%		4.95%		6.20%
Maturity date, year and month			2025-01					2025-01		2025-01
7.50% Senior Notes due February 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate						7.50%	7.50%
Maturity date, year and month							2018-02
Repayments of long-term debt							$ 212
7.15% Senior Notes due June 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate						7.15%	7.15%
Maturity date, year and month							2018-06
Repayments of long-term debt							$ 26
7.50% Senior Notes due April 2026 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes	$ 650				$ 650				$ 650
Stated interest rate	7.50%				7.50%			7.50%	7.50%	7.50%
Maturity date, year and month	2026-04							2026-04		2026-04
2015 Term Loan due December 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	$ 327
7.75% Senior Notes due October 2027 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes	$ 500				$ 500				$ 500
Stated interest rate	7.75%				7.75%			7.75%	7.75%	7.75%
Maturity date, year and month	2027-10							2027-10		2027-10
4.10% Senior Notes due March 2022 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate								4.10%		4.10%
Maturity date, year and month								2022-03		2022-03
Maximum [Member] \| 4.05% Senior Notes due January 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate													6.05%
Maximum [Member] \| 4.95% Senior Notes due January 2025 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate													6.95%
Scenario, Forecast [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Repayments of long-term debt				$ 900
Scenario, Forecast [Member] \| 4.05% Senior Notes due January 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Repayments of long-term debt				40
Scenario, Forecast [Member] \| 4.95% Senior Notes due January 2025 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Repayments of long-term debt				73
Scenario, Forecast [Member] \| 4.10% Senior Notes due March 2022 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Repayments of long-term debt				$ 787