v3.8.0.1

Debt - Schedule Of Debt (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2016	Jun. 30, 2016	Feb. 29, 2016	Apr. 30, 2014
Debt Instrument [Line Items]
Fair value of interest rate swap agreements	$ (71,000,000)	$ (58,000,000)
Total senior notes	4,535,000,000	4,550,000,000
Mortgage notes payable	61,000,000	64,000,000
Capital leases and other	18,000,000	18,000,000
Debt issuance costs	(65,000,000)	(77,000,000)
Total debt	4,699,000,000	4,655,000,000
Less current portion	(4,000,000)	(4,000,000)
Long-term debt	4,695,000,000	4,651,000,000
Revolving credit agreement
Debt Instrument [Line Items]
Revolving credit agreement	150,000,000	100,000,000
Total senior notes | $1,400 million 5.625% Senior notes, due February 15, 2021
Debt Instrument [Line Items]
Face amount	$ 1,400,000,000				$ 1,400,000,000
Interest rate stated, percentage	5.625%				5.625%
Senior notes	$ 1,400,000,000	1,400,000,000
Total senior notes | $1,000 million 4.75% Senior notes, due May 15, 2022
Debt Instrument [Line Items]
Face amount	$ 1,000,000,000					$ 500,000,000
Interest rate stated, percentage	4.75%			4.75%		4.75%
Senior notes	$ 1,006,000,000	1,008,000,000
Total senior notes | $1,000 million 6.125% Senior notes, due February 15, 2024
Debt Instrument [Line Items]
Face amount	$ 1,000,000,000				$ 1,000,000,000
Interest rate stated, percentage	6.125%				6.125%
Senior notes	$ 1,000,000,000	1,000,000,000
Total senior notes | $1,200 million 4.75% Senior notes, due January 15, 2025
Debt Instrument [Line Items]
Face amount	$ 1,200,000,000		$ 1,200,000,000
Interest rate stated, percentage	4.75%		4.75%
Senior notes	$ 1,200,000,000	$ 1,200,000,000

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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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

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

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Fair value as of the balance sheet date of interest rate derivative assets, net of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including the current and noncurrent portions, 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). Senior note holders are paid off in full before any payments are made to junior note holders.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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