Intangible Contract Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Intangible Contract Assets and Liabilities Disclosure [Abstract]

Schedule Of Intangible Assets And Liabilities [Table Text Block]

The balances, net of accumulated amortization, and respective balance sheet classifications at December 31, 2019 and 2018, are set forth in the following tables:

	December 31, 2019
	Assets		Liabilities			Net Total
	(Dollars in millions)
Coal supply agreements	$	20.7	$	(21.4	)	$	(0.7	)
Take-or-pay contracts	—		(40.0		)	(40.0		)
Total	$	20.7	$	(61.4	)	$	(40.7	)
Balance sheet classification:
Investments and other assets	$	20.7	$	—		$	20.7
Accounts payable and accrued expenses	—		(8.4		)	(8.4		)
Other noncurrent liabilities	—		(53.0		)	(53.0		)
Total	$	20.7	$	(61.4	)	$	(40.7	)

	December 31, 2018
	Assets		Liabilities			Net Total
	(Dollars in millions)
Coal supply agreements	$	70.9	$	(32.9	)	$	38.0
Take-or-pay contracts	—		(57.1		)	(57.1		)
Total	$	70.9	$	(90.0	)	$	(19.1	)
Balance sheet classification:
Investments and other assets	$	70.9	$	—		$	70.9
Accounts payable and accrued expenses	—		(20.3		)	(20.3		)
Other noncurrent liabilities	—		(69.7		)	(69.7		)
Total	$	70.9	$	(90.0	)	$	(19.1	)