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- Definition

Senior Note Maturity Year

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- Definition

Tender Offer

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- Definition

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

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- Definition

The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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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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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Fair value amount of debt instrument that was repurchased.

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Face (par) amount of the original debt instrument that was repurchased.

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Amount, after accumulated amortization, of debt discount (premium).

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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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Reflects the difference between the fair value of payments made to legally extinguish a debt and its carrying value at that time. This item excludes the write-off of amounts previously capitalized as debt issuance costs.

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Amount of interest capitalized during the period.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Fair value of the amount outstanding under the credit facility.

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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 fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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- Definition

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

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Number of new stock issued during the period.

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Debt (Narrative) (Details)	3 Months Ended					9 Months Ended	10 Months Ended	12 Months Ended
Debt (Narrative) (Details)	Sep. 30, 2016 USD ($) shares	Jun. 30, 2016 shares	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2011 USD ($)	Sep. 30, 2015	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Oct. 01, 2016 USD ($)	Apr. 30, 2015 USD ($)	Mar. 17, 2011 USD ($)
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Price \| $ / shares								$ 14.02
Tender Offer								$ 750,000,000
Debt Instrument, Repurchased Face Amount											$ 24,500,000
Stock Issued During Period, Shares, New Issues \| shares	1,822,432	65,550,000
Gain (Loss) on Extinguishment of Debt								287,800,000	$ (33,500,000)	$ 0
Interest Expense								228,800,000	216,300,000	161,400,000
Capitalized interest								$ 45,700,000	$ 87,400,000	78,200,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage									100.00%
Debentures Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage									0.00%
3.00% Exchangeable senior notes due 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								3.00%
5.20% Senior notes due 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								5.20%
5.75% Senior notes due 2044
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								5.75%
4.50% Senior notes due 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								4.50%
4.70% Senior notes due 2021
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								4.70%
6.875% Senior notes due 2020
Debt Instrument [Line Items]
Senior Note Maturity Year								2020
Debt instrument, interest rate, stated percentage								6.875%
8.50% Senior notes due 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								8.50%
7.875% Senior notes due 2040
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								7.875%
7.20% Senior notes due 2027
Debt Instrument [Line Items]
Senior Note Maturity Year								2027
Debt instrument, interest rate, stated percentage								7.20%
Tender Offer [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount								$ 860,700,000
Debt Instrument, Repurchase Amount								622,300,000
Open Market Repurchases [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount								269,900,000
Debt Instrument, Repurchase Amount								241,600,000
Revolving Credit Facility [Member] \| Five Year Credit Facility Member
Debt Instrument [Line Items]
Current borrowing capacity							$ 2,250,000,000		$ 2,250,000,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage									0.225%
Maximum amount of right to increase the commitment							500,000,000		$ 500,000,000
Line of Credit Facility, Fair Value of Amount Outstanding							$ 0		$ 0
Revolving Credit Facility [Member] \| Credit Facility due 2019 [Member]
Debt Instrument [Line Items]
Current borrowing capacity	$ 1,130,000,000
Revolving Credit Facility [Member] \| Base Rate [Member] \| Five Year Credit Facility Member
Debt Instrument [Line Items]
Basis spread on variable rate									0.50%
Revolving Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Five Year Credit Facility Member
Debt Instrument [Line Items]
Basis spread on variable rate									1.50%
Convertible Debt [Member] \| 3.00% Exchangeable senior notes due 2024
Debt Instrument [Line Items]
Debt Instrument, Face Amount								$ 849,500,000
Senior Note Maturity Year								2024
Conversion rate per $1,000 principal amount of shares								71.3343
Proceeds from Issuance of Long-term Debt								$ 822,800,000
Debt instrument, interest rate, stated percentage								8.00%
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount								$ 1,130,600,000			24,500,000
Debt Instrument, Repurchase Amount								863,900,000
Senior Notes [Member] \| 5.20% Senior notes due 2025
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 700,000,000
Senior Note Maturity Year			2025
Debt instrument, interest rate, stated percentage			5.20%
Debt Instrument, Unamortized Discount (Premium), Net			$ 2,600,000
Debt Instrument, Repurchased Face Amount								30,700,000
Debt Instrument, Repurchase Amount								16,800,000
Senior Notes [Member] \| 5.75% Senior notes due 2044
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 400,000,000	$ 625,000,000
Senior Note Maturity Year				2044
Debt instrument, interest rate, stated percentage			5.75%	5.75%
Debt Instrument, Unamortized Discount (Premium), Net			$ 18,700,000							2,800,000
Debt Instrument, Repurchased Face Amount											$ 24,500,000
Gain (Loss) on Extinguishment of Debt								8,800,000
Senior Notes [Member] \| 4.50% Senior notes due 2024
Debt Instrument [Line Items]
Debt Instrument, Face Amount										$ 625,000,000
Senior Note Maturity Year										2024
Debt instrument, interest rate, stated percentage										4.50%
Debt Instrument, Unamortized Discount (Premium), Net										$ 850,000
Debt Instrument, Repurchased Face Amount								1,700,000
Debt Instrument, Repurchase Amount								900,000
Senior Notes [Member] \| 4.70% Senior notes due 2021
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 1,500,000,000
Senior Note Maturity Year					2021
Debt instrument, interest rate, stated percentage					4.70%
Debt Instrument, Unamortized Discount (Premium), Net					$ 29,600,000
Debt Instrument, Repurchased Face Amount								817,000,000
Debt Instrument, Repurchase Amount								609,000,000
Senior Notes [Member] \| 6.875% Senior notes due 2020
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 900,000,000
Senior Note Maturity Year					2020
Debt instrument, interest rate, stated percentage					6.875%
Debt Instrument, Repurchased Face Amount								219,200,000
Debt Instrument, Repurchase Amount								181,500,000
Senior Notes [Member] \| 8.50% Senior notes due 2019
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 500,000,000
Senior Note Maturity Year					2019				2019
Debt instrument, interest rate, stated percentage					8.50%		8.50%		8.50%
Debt Instrument, Repurchased Face Amount								62,000,000
Debt Instrument, Repurchase Amount								55,700,000
Senior Notes [Member] \| 7.875% Senior notes due 2040
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 300,000,000
Senior Note Maturity Year					2040
Debt instrument, interest rate, stated percentage					7.875%
Senior Notes [Member] \| 7.20% Senior notes due 2027
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 150,000,000		$ 150,000,000
Debt instrument, interest rate, stated percentage							7.20%		7.20%
Senior Notes [Member] \| 8.00% Senior notes due 2024
Debt Instrument [Line Items]
Senior Note Maturity Year									2024
Debt instrument, interest rate, stated percentage							8.00%		8.00%
Senior Notes [Member] \| Three Point Two Five Percent Senior Notes Member
Debt Instrument [Line Items]
Debt Instrument, Face Amount													$ 1,000,000,000
Senior Note Maturity Year						2016
Debt instrument, interest rate, stated percentage													3.25%
Gain (Loss) on Extinguishment of Debt, before Write off of Debt Issuance Cost									$ 30,400,000
Senior Notes [Member] \| Tender Offers and Open Market Repurchases [Member]
Debt Instrument [Line Items]
Gain (Loss) on Extinguishment of Debt								$ 279,000,000
Bonds [Member] \| Four Point Three Three Percent and Four Point Six Five Percent Maritime Administration Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount												$ 65,300,000
Gain (Loss) on Extinguishment of Debt									$ 3,100,000
Bonds [Member] \| Four Point Six Five Percent Marine Administration Bonds Including Current Maturities Member
Debt Instrument [Line Items]
Senior Note Maturity Year									2020
Debt instrument, interest rate, stated percentage												4.65%
Acquired Debt [Member] \| Four Point Three Three Percent Marine Administration Bonds Including Current Maturities Member
Debt Instrument [Line Items]
Senior Note Maturity Year									2016
Debt instrument, interest rate, stated percentage												4.33%
Maximum [Member] \| Revolving Credit Facility [Member] \| Five Year Credit Facility Member
Debt Instrument [Line Items]
Maximum Percent of Debt to Total Capitalization Ratio							60.00%