Maximum term of capital lease period in Years

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Defined Benefit Plan, Lease term of contributed property

+ References

No definition available.

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- Definition

Represents the issue price of the senior unsecured note expressed as a percentage of principal amount of the instrument.

+ References

No definition available.

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- Definition

Line of credit facility, Threshold amount outstanding before funding of dividend payments

+ References

No definition available.

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- Definition

Long Term Debt Assumed in Acquisition

+ References

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Pension Building Contribution Aggregate Annual Rent

+ References

No definition available.

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- Definition

Maximum term of the lease(s) related to the assets being leased-back in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

+ References

No definition available.

+ Details

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- Definition

Minimum term of the lease(s) related to the assets being leased-back in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

+ References

No definition available.

+ Details

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- Definition

Value of property contributed in noncash investing and financing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
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- Definition

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.

+ References

+ Details

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- Definition

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.

+ References

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- Definition

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

+ References

No definition available.

+ Details

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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
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-SubTopic 30
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-Paragraph 8
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- Definition

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

+ References

+ Details

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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.

+ Details

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- Definition

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

+ References

+ Details

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Amount of increase (decrease) in plan assets of defined benefit plan from assets transferred into (from) plan.

+ References

No definition available.

+ Details

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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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- Definition

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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+ Details

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Period Type:	instant

- Definition

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.

+ References

+ Details

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- Definition

Amount of the required periodic payment applied to principal.

+ References

+ Details

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- Definition

Secured financing other than securities sold under agreements to repurchase and securities loaned.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 15
-Paragraph 83
-URI http://asc.fasb.org/extlink&oid=77898254&loc=d3e34841-113949

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- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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Long-Term Debt (Narrative) (Details) - USD ($)	12 Months Ended
Long-Term Debt (Narrative) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Issue price expressed as a percentage of principal amount (in hundredths)	100.00%
Proceeds from debt, net of issuance costs			$ 6,485,000,000
Loss on early extinguishment of debt	$ (88,000,000)	$ (7,000,000)
Financing obligation for contribution of real property to pension plan		15,000,000
Fair value of property contributed to plan		15,000,000
Pension Building Contribution Aggregate Annual Rent		2,000,000
Lease term of contributed property	15 years
Sale and leaseback term, minimum (in years)	12 years
Sale and leaseback term, maximum (in years)	23 years
Capital Lease Term, minimum years	1 year
Capital Lease Term, maximum years	7 years
2016 Pension Real Estate Contributions [Member]
Debt Instrument [Line Items]
Financing obligation for contribution of real property to pension plan		15,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility maximum borrowing capacity	$ 134,000,000
Long-term Line of Credit	$ 63,000,000	0
Senior Notes 7.875% [Member]
Debt Instrument [Line Items]
Interest Rate			7.875%
Payments to retire debt			$ 97,000,000
Senior Notes 6.625% [Member]
Debt Instrument [Line Items]
Interest Rate			6.625%
Payments to retire debt			$ 105,000,000
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%
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%
Senior Note Due 9/15/2022 [Member] \| Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 188,000,000
Interest Rate		10.50%
Secured Equipment Financing [Member]
Debt Instrument [Line Items]
Secured equipment financing			$ 3,000,000
Secured equipment financing term	4 years
CTF Transaction [Member]
Debt Instrument [Line Items]
Long Term Debt Assumed		$ 600,000,000
CTF Transaction [Member] \| Subsidiary Senior Note Due 5/15/2027 [Member]
Debt Instrument [Line Items]
Interest Rate		6.75%
Long Term Debt Assumed		$ 200,000,000
CTF Transaction [Member] \| Subsidiary Senior Note Due 2/1/2028 [Member]
Debt Instrument [Line Items]
Interest Rate		6.86%
Long Term Debt Assumed		$ 300,000,000
CTF Transaction [Member] \| Subsidiary Senior Note Due 11/15/2031 [Member]
Debt Instrument [Line Items]
Interest Rate		8.50%
Long Term Debt Assumed		$ 100,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 4/15/2017 [Member]
Debt Instrument [Line Items]
Interest Rate	8.25%	8.25%
Debt instrument, maturity date	Apr. 15, 2017
Payments to retire debt	$ 210,000,000
Senior Unsecured Debt [Member] \| Senior Note 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	$ 92,000,000
Senior 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	$ 30,000,000
Senior 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
Payments to retire debt	$ 550,000,000
Senior Unsecured Debt [Member] \| Senior Note Due 9/15/2020 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,000,000,000
Interest Rate	8.875%	8.875%
Debt instrument, maturity date	Sep. 15, 2020
Payments to retire debt	$ 763,000,000
Senior 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
Payments to retire debt	$ 10,000,000
Senior 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
Senior Unsecured Debt [Member] \| Senior Note Due 9/15/2022 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 2,000,000,000
Interest Rate	10.50%	10.50%
Debt instrument, maturity date	Sep. 15, 2022
Senior 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
Senior Unsecured Debt [Member] \| Senior Note Due 9/15/2025 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 3,600,000,000
Interest Rate	11.00%	11.00%
Debt instrument, maturity date	Sep. 15, 2025
Senior Unsecured Debt [Member] \| CTF Transaction [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 6,600,000,000
Senior Secured Debt [Member] \| CoBank Due 10/24/2019 [Member]
Debt Instrument [Line Items]
Interest Rate	5.445%	4.145%
Debt instrument, maturity date	Oct. 24, 2019
Repayment of the outstanding principal balance, quarterly installments amount	$ 9,000,000
Senior Secured Debt [Member] \| CoBank Due 10/21/2021 Member
Debt Instrument [Line Items]
Debt instrument, face amount	$ 315,000,000
Interest Rate	5.445%	4.145%
Debt instrument, maturity date	Oct. 12, 2021
Repayment of the outstanding principal balance, quarterly installments amount	$ 8,000,000
Senior Secured Debt [Member] \| 2014 And 2016 CoBank Credit Agreements [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	3.875%
Subsidiary Debentures Due [Member] \| Subsidiary Senior Note Due 5/15/2027 [Member]
Debt Instrument [Line Items]
Interest Rate	6.75%	6.75%
Debt instrument, maturity date	May 15, 2027
Subsidiary Debentures Due [Member] \| Subsidiary Senior Note Due 2/1/2028 [Member]
Debt Instrument [Line Items]
Interest Rate	6.86%	6.86%
Debt instrument, maturity date	Feb. 01, 2028
Subsidiary Debentures Due [Member] \| Subsidiary Senior Note Due 11/15/2031 [Member]
Debt Instrument [Line Items]
Interest Rate	8.50%	8.50%
Debt instrument, maturity date	Nov. 15, 2031
JP Morgan Term Loan A [Member] \| Senior Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,625,000,000
Interest Rate	4.32%	3.27%
Debt instrument, maturity date	Mar. 31, 2021
JP Morgan Term Loan A [Member] \| Senior Secured Debt [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	2.75%
JP Morgan Term Loan B [Member] \| Senior Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,500,000,000
Interest Rate	5.32%
Debt instrument, maturity date	Jun. 15, 2024
JP Morgan Term Loan B [Member] \| Senior Secured Debt [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	2.75%
JP Morgan Term Loan B [Member] \| Senior Secured Debt [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
JP Morgan Combined Credit Facility [Member]
Debt Instrument [Line Items]
Amount outstanding before facility can be used to fund dividend payments	$ 250,000,000
Days Prior To Maturity To Meet Threshold To Not Accelerate Debt	91 days
Maximum Debt Threshold To Not Accelerate Debt	$ 500,000,000
Minimum [Member] \| Senior Secured Debt [Member] \| 2014 And 2016 CoBank Credit Agreements [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	0.875%
Minimum [Member] \| Senior Secured Debt [Member] \| 2014 And 2016 CoBank Credit Agreements [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	1.875%
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%
Maximum [Member] \| Senior Secured Debt [Member] \| 2014 And 2016 CoBank Credit Agreements [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	3.875%
Maximum [Member] \| Senior Secured Debt [Member] \| 2014 And 2016 CoBank Credit Agreements [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	4.875%
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%