Maximum term of capital lease period in Years

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Minimum Term of Capital Leases for repayment based on expiration date of original lease contract

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Number of days prior to the maturity date at which the maximum debt threshold must be met in order to not accelerate the debt.

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The effective basis spread used to determine the effective interest rate.

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Defined Benefit Plan, Lease term of contributed property

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Gain (loss) on contribution of property to defined benefit

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Long Term Debt Assumed in Acquisition

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Maximum debt threshold amount that much be reached in order to not accelerated the debt maturity.

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Pension Building Contribution Aggregate Annual Rent

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Value of property contributed in noncash investing and financing activities.

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The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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

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Fair value amount of debt instrument that was repurchased.

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Description of a subjective acceleration clause that is a part of the debt instrument. A subjective acceleration clause is a provision in a debt agreement that states that the creditor may accelerate the scheduled maturities of the obligation under conditions that are not objectively determinable (for example, if the debtor fails to maintain satisfactory operations or if a material adverse change occurs).

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Amount of gain (loss) from the difference between the repurchase price of a debt instrument initially issued by the entity and the net carrying amount of the debt at the time of its repurchase.

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

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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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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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The cash outflow from a repayment of a borrowing having initial term of repayment of more than three months. Includes repayments of short-term and long-term debt.

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The liability due as of the balance sheet date for leasebacks accounted for using the deposit method.

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Long-Term Debt (Narrative) (Details) - USD ($)			12 Months Ended
Long-Term Debt (Narrative) (Details) - USD ($)	Oct. 01, 2018	Jul. 03, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jul. 03, 2018	Mar. 19, 2018	Jun. 15, 2017
Debt Instrument [Line Items]
Payment to retire debt instruments			$ 2,828,000,000
Loss on early extinguishment of debt			32,000,000	$ (88,000,000)	$ (7,000,000)
Gain on extinguishment of debt			32,000,000
Financing obligation for contributions of real property to pension plan			37,000,000		15,000,000
Pension Building Contribution Aggregate Annual Rent			$ 5,000,000		$ 2,000,000
Lease term of contributed property			20 years		15 years
Gain (loss) on contribution of property to defined benefit					$ 0
Capital Lease Term, minimum years			1 year
Capital Lease Term, maximum years			7 years
Proceeds from long-term debt borrowings			$ 1,840,000,000	1,500,000,000	1,940,000,000
Remaining outstanding principal			17,400,000,000	$ 17,863,000,000
Sale leaseback transaction			37,000,000		15,000,000
2016 Pension Real Estate Contributions [Member]
Debt Instrument [Line Items]
Financing obligation for contributions of real property to pension plan					15,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, current borrowings			71,000,000
Senior Note Due 11/1/2025 [Member] \| Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount					$ 188,000,000
Interest Rate					10.50%
Senior Note Due 4/15/2020 [Member] \| Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount					$ 147,000,000
Interest Rate					8.50%
Senior Note Due 9/15/2020 [Member] \| Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount					$ 66,000,000
Interest Rate					8.875%
Term Loan Due 06/15/2024 [Member]
Debt Instrument [Line Items]
Proceeds from long-term debt borrowings		$ 240,000,000	240,000,000
Senior Note Due 4/15/2017 [Member] \| Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Original Debt, Amount					$ 397,000,000
Interest Rate					8.25%
CTF Acquisition [Member]
Debt Instrument [Line Items]
Long Term Debt Assumed					$ 600,000,000
CTF Acquisition [Member] \| Subsidiary Senior Note Due 11/15/2031 [Member]
Debt Instrument [Line Items]
Interest Rate					8.50%
Long Term Debt Assumed					$ 100,000,000
CTF Acquisition [Member] \| Subsidiary Senior Note Due 05/15/2027 [Member]
Debt Instrument [Line Items]
Interest Rate					6.75%
Long Term Debt Assumed					$ 200,000,000
CTF Acquisition [Member] \| Subsidiary Senior Note Due 2/1/2028 [Member]
Debt Instrument [Line Items]
Interest Rate					6.86%
Long Term Debt Assumed					$ 300,000,000
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Payments to retire debt			117,000,000
Remaining outstanding principal			$ 500,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 7/1/2021 [Member]
Debt Instrument [Line Items]
Interest Rate				9.25%
Debt instrument, maturity date				Jul. 01, 2021
Payments to retire debt				$ 10,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 10/1/2018 [Member]
Debt Instrument [Line Items]
Interest Rate				8.125%
Debt instrument, maturity date			Oct. 01, 2018
Payments to retire debt				$ 92,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 4/15/2020 [Member]
Debt Instrument [Line Items]
Interest Rate				8.50%
Debt instrument, maturity date				Apr. 15, 2020
Payments to retire debt				$ 550,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 9/15/2020 [Member]
Debt Instrument [Line Items]
Interest Rate				8.875%
Debt instrument, maturity date				Sep. 15, 2020
Payments to retire debt				$ 763,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 3/15/2019 [Member]
Debt Instrument [Line Items]
Interest Rate				7.125%
Debt instrument, maturity date				Mar. 15, 2019
Payments to retire debt				$ 30,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 4/15/2017 [Member]
Debt Instrument [Line Items]
Interest Rate				8.25%
Payments to retire debt				$ 210,000,000
Secured Debt [Member]
Debt Instrument [Line Items]
Payment to retire debt instruments			$ 828,000,000
Remaining outstanding principal			5,246,000,000	$ 3,511,000,000
Secured Debt [Member] \| Second Lien Notes Due 4/1/2026 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 1,600,000,000				$ 1,600,000,000
Interest Rate			8.50%				8.50%
Debt instrument, maturity date			Apr. 01, 2026
Remaining outstanding principal			$ 1,600,000,000
Secured Debt [Member] \| Term Loan Due 06/15/2024 [Member]
Debt Instrument [Line Items]
Interest Rate			6.28%	5.32%
Debt instrument, maturity date			Jun. 15, 2024
Remaining outstanding principal			$ 1,716,000,000	$ 1,492,000,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Remaining outstanding principal			$ 11,297,000,000	$ 13,495,000,000
Unsecured Debt [Member] \| Senior Note Due 7/1/2021 [Member]
Debt Instrument [Line Items]
Interest Rate			9.25%	9.25%
Debt instrument, maturity date			Jul. 01, 2021
Payment to retire debt instruments			$ 400,000,000
Remaining outstanding principal			$ 89,000,000	$ 490,000,000
Unsecured Debt [Member] \| Senior Note Due 9/15/2021 [Member]
Debt Instrument [Line Items]
Interest Rate			6.25%	6.25%
Debt instrument, maturity date			Sep. 15, 2021
Payment to retire debt instruments			$ 555,000,000
Remaining outstanding principal			$ 220,000,000	$ 775,000,000
Unsecured Debt [Member] \| Senior Note Due 4/15/2022 [Member]
Debt Instrument [Line Items]
Interest Rate			8.75%	8.75%
Debt instrument, maturity date			Apr. 15, 2022
Remaining outstanding principal			$ 500,000,000	$ 500,000,000
Unsecured Debt [Member] \| Senior Note Due 9/15/2022 [Member]
Debt Instrument [Line Items]
Interest Rate			10.50%	10.50%
Debt instrument, maturity date			Sep. 15, 2022
Remaining outstanding principal			$ 2,188,000,000	$ 2,188,000,000
Unsecured Debt [Member] \| Senior Note Due 1/15/2023 [Member]
Debt Instrument [Line Items]
Interest Rate			7.125%	7.125%
Debt instrument, maturity date			Jan. 15, 2023
Remaining outstanding principal			$ 850,000,000	$ 850,000,000
Unsecured Debt [Member] \| Senior Note Due 4/15/2024 [Member]
Debt Instrument [Line Items]
Interest Rate			7.625%	7.625%
Debt instrument, maturity date			Apr. 15, 2024
Remaining outstanding principal			$ 750,000,000	$ 750,000,000
Unsecured Debt [Member] \| Senior Note Due 1/15/2025 [Member]
Debt Instrument [Line Items]
Interest Rate			6.875%	6.875%
Debt instrument, maturity date			Jan. 15, 2025
Remaining outstanding principal			$ 775,000,000	$ 775,000,000
Unsecured Debt [Member] \| Senior Note Due 11/1/2025 [Member]
Debt Instrument [Line Items]
Interest Rate			7.00%	7.00%
Debt instrument, maturity date			Nov. 01, 2025
Remaining outstanding principal			$ 138,000,000	$ 138,000,000
Unsecured Debt [Member] \| Senior Note Due 8/15/2031 [Member]
Debt Instrument [Line Items]
Interest Rate			9.00%	9.00%
Debt instrument, maturity date			Aug. 15, 2031
Remaining outstanding principal			$ 945,000,000	$ 945,000,000
Unsecured Debt [Member] \| Debentures Due 10/1/2034 [Member]
Debt Instrument [Line Items]
Interest Rate			7.68%	7.68%
Debt instrument, maturity date			Oct. 01, 2034
Remaining outstanding principal			$ 1,000,000	$ 1,000,000
Unsecured Debt [Member] \| Senior Notes Due 10/1/2018 [Member]
Debt Instrument [Line Items]
Interest Rate			8.125%	8.125%
Debt instrument, maturity date			Oct. 01, 2018
Payments to retire debt			$ 61,000,000
Payment to retire debt instruments	$ 431,000,000
Remaining outstanding principal				$ 491,000,000
Unsecured Debt [Member] \| Senior Note Due 4/15/2020 [Member]
Debt Instrument [Line Items]
Interest Rate			8.50%	8.50%
Debt instrument, maturity date			Apr. 15, 2020
Repurchase of senior notes			$ 447,000,000
Remaining outstanding principal			$ 172,000,000	$ 619,000,000
Unsecured Debt [Member] \| Senior Note Due 9/15/2020 [Member]
Debt Instrument [Line Items]
Interest Rate			8.875%	8.875%
Debt instrument, maturity date			Sep. 15, 2020
Payment to retire debt instruments			$ 249,000,000
Remaining outstanding principal			$ 55,000,000	$ 303,000,000
Unsecured Debt [Member] \| Senior Note Due 3/15/2019 [Member]
Debt Instrument [Line Items]
Interest Rate			7.125%	7.125%
Debt instrument, maturity date			Mar. 15, 2019
Payments to retire debt			$ 56,000,000
Remaining outstanding principal			348,000,000	$ 404,000,000
Unsecured Debt Excluding Open Market Purchases [Member]
Debt Instrument [Line Items]
Payment to retire debt instruments			1,651,000,000
JP Morgan Term Loan A [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 1,625,000,000
Debt instrument, maturity date			Mar. 31, 2021
JP Morgan Term Loan A [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Effective basis spread			2.75%
JP Morgan Term Loan B [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 1,740,000,000					$ 1,500,000,000
Debt instrument, maturity date			Jun. 15, 2024
JP Morgan Term Loan B [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin			2.75%
JP Morgan Term Loan B [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin			3.75%
JP Morgan Revolving Credit Facility 2015 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date			Feb. 27, 2022
Line of credit facility maximum borrowing capacity			$ 850,000,000
Line of credit facility, current borrowings			$ 275,000,000
JP Morgan Combined Credit Facility [Member]
Debt Instrument [Line Items]
Days Prior To Maturity To Meet Threshold To Not Accelerate Debt			91 days
Maximum Debt Threshold To Not Accelerate Debt			$ 500,000,000
Debt Instrument, Acceleration Cause			The maturities of the Term Loan A, the Revolver, and the Term Loan B, in each case if still outstanding, will be accelerated in the following circumstances: (i) if, 91 days before the maturity date of any series of Senior Notes maturing in 2020, 2023 and 2024, more than $500 million in principal amount remains outstanding on such series; or (ii) if, 91 days before the maturity date of the first series of Senior Notes maturing in 2021 or 2022, more than $500 million in principal amount remains outstanding, in the aggregate, on the two series of Senior Notes maturing in such year. . As of December 31, 2018, less than $500 million in principal amount remains outstanding on the senior notes due 2020 and on the two series of senior notes maturing in 2021.
CoBank Term Loan 2016 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 315,000,000
CoBank Term Loan 2014 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount						$ 350,000,000
COBANK Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin			4.875%
Minimum [Member] \| JP Morgan Term Loan A And Revolver [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin			0.75%
Minimum [Member] \| JP Morgan Term Loan A And Revolver [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin			1.75%
Minimum [Member] \| COBANK Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin			0.875%
Minimum [Member] \| COBANK Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin			1.875%
Maximum [Member] \| JP Morgan Term Loan A And Revolver [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin			1.75%
Maximum [Member] \| JP Morgan Term Loan A And Revolver [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin			2.75%
Maximum [Member] \| COBANK Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin			3.875%
Maximum [Member] \| COBANK Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin			4.875%