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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

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Debt - Debt (Details) $ in Millions	1 Months Ended
Debt - Debt (Details) $ in Millions	Jun. 17, 2019	Jun. 30, 2019 USD ($)	Jun. 30, 2019 AUD ($)	May 23, 2019 USD ($)	Jan. 15, 2019 USD ($)	Oct. 04, 2013
Debt Instruments [Line Items]
Registration Payment Arrangement, Term	three
Club Facility [Member]
Debt Instruments [Line Items]
Letters of Credit Outstanding, Amount		$ 165,000,000	$ 60
Bilateral Facility [Member]
Debt Instruments [Line Items]
Letters of Credit Outstanding, Amount		8,000,000
Debt Instrument, Unused Borrowing Capacity, Amount		17,000,000
Club & Bilateral Facility [Member]
Debt Instruments [Line Items]
Cash Collateral for Borrowed Securities		1,000,000
Australian Dollar Facility [Member] [Member]
Debt Instruments [Line Items]
Letters of Credit Outstanding, Amount		$ 24,000,000
Senior Note Six Point Zero Percent Due in Two Thousand Nineteen [Member] \| Senior Notes
Debt Instruments [Line Items]
Repayment of debt					$ 413,000,000
Interest rate					6.00%
Senior Note Five Point Seven Five Percent Due in Two Thousand Twenty Three [Member] \| Senior Notes
Debt Instruments [Line Items]
Interest rate						5.75%
Senior Notes				$ 265,000,000
Debt Instrument, Fair Value Disclosure				$ 284,000,000
Debt Instrument, Interest Rate, Effective Percentage				4.00%