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

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

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

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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-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

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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.

+ References

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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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 ($)		1 Months Ended				6 Months Ended	12 Months Ended
Debt (Senior Notes - Narrative) (Details) - USD ($)	Apr. 26, 2018	Dec. 31, 2018	Sep. 30, 2017	Jul. 31, 2016	Jan. 31, 2015	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jul. 31, 2018
Debt Instrument [Line Items]
Loss on early extinguishment of debt	$ 8,000,000						$ 17,000,000	$ 70,000,000	$ 51,000,000
Repayments of long-term debt							$ 2,095,000,000	1,139,000,000	$ 1,175,000,000
Repayment of short-term debt								$ 328,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt			$ 1,100,000,000
Loss on early extinguishment of debt		$ 9,000,000	59,000,000			$ 11,000,000
Payment of premiums		2,000,000	53,000,000
Repayments of long-term debt		$ 900,000,000		$ 700,000,000
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%
4.05% Senior Notes due January 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate		4.05%					4.05%
Debt, maturity date							Jan. 31, 2020
4.05% Senior Notes due January 2020 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes					$ 850,000,000
Stated interest rate		4.05%		5.80%	4.05%		4.05%	4.05%		5.30%
Debt, maturity date							Jan. 31, 2020	Jan. 31, 2020
Repayments of long-term debt		$ 40,000,000
4.95% Senior Notes due January 2025 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes					$ 1,000,000,000
Stated interest rate		4.95%		6.70%	4.95%		4.95%	4.95%		6.20%
Debt, maturity date							Jan. 31, 2025	Jan. 31, 2025
Repayments of long-term debt		$ 73,000,000
3.30% Senior Notes due January 2018 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate		3.30%					3.30%
Debt, maturity date							Jan. 31, 2018
Repayments of long-term debt						38,000,000
7.5% Senior Notes due 2018 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate		7.50%					7.50%
Debt, maturity date							Feb. 28, 2018
Repayments of long-term debt						212,000,000
7.15% Senior Notes due 2018 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate		7.15%					7.15%
Debt, maturity date							Jun. 30, 2018
Repayments of long-term debt						$ 26,000,000
7.50% Senior Notes due April 2026 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes			$ 650,000,000
Stated interest rate		7.50%	7.50%				7.50%	7.50%
Debt, maturity date							Apr. 30, 2026	Apr. 30, 2026
7.75% Senior Notes due October 2027 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes			$ 500,000,000
Stated interest rate		7.75%	7.75%				7.75%	7.75%
Debt, maturity date							Oct. 31, 2027	Oct. 31, 2027
2020 Senior Notes [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Repayments of long-term debt			$ 758,000,000
2015 Term Loan due December 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Repayments of long-term debt				$ 375,000,000
2015 Term Loan due December 2020 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Repayments of long-term debt			$ 327,000,000
4.10% Senior Notes Due 2022 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate		4.10%					4.10%	4.10%
Debt, maturity date							Mar. 31, 2022	Mar. 31, 2022
Repayments of long-term debt		$ 787,000,000
Maximum [Member] \| 4.05% Senior Notes due January 2020 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate				6.05%
Maximum [Member] \| 4.95% Senior Notes due January 2025 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate				6.95%