| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 78.5 | -6.2 | -5.3 | 0.3 | 3.2 | 306.9 | 417.8 | 236.0 |
| Depreciation and amortization | 159.0 | 84.7 | 78.0 | 64.0 | 49.4 | 366.2 | 333.1 | 306.3 |
| Asset impairment charges | | | | | | 35.9 | | |
| Stock-based compensation | | | | | | 7.9 | 7.6 | 6.6 |
| Change in working capital | 1.1 | 0.8 | | -2.5 | 0.3 | -15.4 | -5.2 | -22.3 |
| Other | 1.1 | 0.8 | | -2.5 | 0.3 | -15.4 | -5.2 | -22.3 |
| Other operating activities | -34.4 | -66.8 | -24.8 | -3.9 | 0.6 | -309.3 | -376.8 | -166.7 |
| Cash from operations | 204.2 | 12.6 | 47.8 | 57.9 | 53.5 | 392.1 | 376.5 | 359.9 |
| |
| Capital expenditures [+] | 237.5 | 177.8 | 23.9 | -39.3 | -37.8 | -358.1 | -354.2 | -373.8 |
| Purchases of property and equipment | 237.5 | 177.8 | 23.9 | -39.3 | -37.8 | -358.1 | -346.6 | -367.2 |
| Capitalized product costs | | | | | | | -7.5 | -6.7 |
| Other cash from investing | -358.3 | -449.2 | -153.2 | -373.5 | | 371.1 | 255.0 | 202.9 |
| Cash from investing | -120.8 | -271.4 | -129.3 | -412.9 | -37.8 | 13.0 | -99.1 | -170.9 |
| |
| Cash dividends paid | 3.0 | | | | | -225.4 | -206.3 | -184.1 |
| Issuance of common stock, net | 23.5 | | | | | | | 366.6 |
| Other cash from financing | -124.8 | 204.7 | 370.1 | 360.2 | -15.9 | -168.3 | -77.7 | -349.7 |
| Cash from financing | -98.3 | 204.7 | 370.1 | 360.2 | -15.9 | -393.7 | -283.9 | -167.2 |
| |
| Free cash flow | 441.8 | 190.4 | 71.7 | 18.6 | 15.6 | 34.0 | 29.9 | -7.3 |
| Per share (diluted) | $2.78 | $1.21 | $0.46 | $0.13 | $0.11 | $0.22 | $0.14 | ($0.09) |
| |
| Cash paid for interest | 45.2 | 43.8 | 22.2 | 17.7 | 19.3 | 196.4 | 200.3 | 207.1 |