CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 345.0	$ (31.0)
Adjustments to reconcile net income (loss) to net cash provided by operations:
Depreciation and amortization	301.2	290.1
Deferred income taxes	(21.9)	(0.7)
Provision for pension and other postretirement benefits	13.0	23.8
Share-based compensation expense	25.9	24.5
Loss on disposals of property and equipment	5.3	2.1
Other postretirement benefit claims paid	(6.6)	(3.5)
Contributions to pension plans	(16.1)	(11.0)
Noncash loss on debt extinguishment	0.3	0.0
Contingent payment derivative	(4.2)	0.0
Asset impairment charges	34.3	329.8
Changes in current assets and liabilities:
Receivables - trade and other	(30.0)	36.9
Prepaid expenses and other current assets	2.1	(8.3)
Accounts payable	(18.3)	28.3
Accrued income taxes	13.6	3.2
Deferred revenues	45.3	12.0
Other current liabilities	(28.6)	(40.1)
Net changes in other noncurrent assets and liabilities	28.3	2.8
Net cash provided by operating activities	688.6	658.9
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(88.5)	(674.8)
Proceeds from disposals of property and equipment	1.1	5.1
Net cash provided by (used in) investing activities	(87.4)	(669.7)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from borrowings	0.0	220.0
Reductions of long-term debt	(47.9)	(220.0)
Dividends paid	0.0	(37.9)
Net cash provided by (used in) financing activities	(47.9)	(37.9)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	553.3	(48.7)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	484.2	339.2
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 1,037.5	$ 290.5