| 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 |
| | 8-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 467.0 | 34.1 | -9.8 | 76.0 | 153.0 | 67.6 | 41.5 | 307.0 |
| Depreciation and amortization | 226.9 | 224.6 | 210.8 | 207.1 | 201.3 | 172.0 | 178.1 | 195.3 |
| Stock-based compensation | | 6.6 | 11.6 | 12.8 | 10.2 | 22.1 | 12.9 | 8.4 |
| Deferred taxes | | -14.8 | 11.7 | -17.4 | -16.5 | 16.6 | 91.5 | 72.6 |
| Change in working capital [+] | -31.2 | 19.2 | -41.0 | -97.6 | 11.9 | -37.9 | 3.4 | -257.0 |
| Accounts receivable | | 44.7 | 11.1 | -39.0 | 39.2 | -44.4 | -17.6 | 63.8 |
| Inventories | | -6.7 | -2.1 | -5.5 | 4.8 | -3.3 | 3.4 | 5.0 |
| Other current assets | | 0.2 | 7.6 | 0.5 | -7.3 | -2.9 | 7.5 | |
| Accounts payable | | 11.5 | -30.8 | -21.7 | 37.5 | 7.0 | -4.2 | -0.6 |
| Other | -31.2 | -30.5 | -26.9 | -31.9 | -62.2 | 5.7 | 14.3 | -325.2 |
| Other operating activities | -11.7 | 35.8 | -53.9 | 63.7 | 53.6 | 7.6 | 1.7 | -34.7 |
| Cash from operations | 651.0 | 305.6 | 129.3 | 244.6 | 413.5 | 248.1 | 329.1 | 291.7 |
| |
| Capital expenditures [+] | -171.5 | -132.8 | -86.0 | -169.7 | -145.7 | -81.4 | -53.6 | -143.1 |
| Purchases of property and equipment | -171.5 | -132.8 | -86.0 | -169.7 | -145.7 | -81.4 | -53.6 | -143.1 |
| Sales of property and equipment | | 13.6 | 9.9 | 2.2 | 2.1 | 24.6 | 7.8 | 12.8 |
| Other cash from investing | 29.3 | -8.2 | -0.2 | -5.0 | -10.0 | | | |
| Cash from investing | -142.2 | -127.4 | -76.3 | -172.5 | -153.6 | -56.8 | -45.8 | -130.3 |
| |
| Cash dividends paid | -71.5 | | | | | | | |
| Repurchase of common stock, net | | | | -32.7 | -25.8 | | | |
| Financing costs | | -2.4 | -9.0 | -12.5 | -2.2 | -32.3 | -0.5 | -16.3 |
| Other cash from financing | -308.6 | -33.2 | -91.4 | -236.4 | -125.3 | -82.9 | -277.2 | -171.3 |
| Cash from financing | -380.1 | -30.9 | -82.4 | -256.7 | -148.9 | -50.6 | -276.7 | -154.9 |
| |
| Free cash flow | 479.5 | 172.8 | 43.3 | 74.8 | 267.8 | 166.7 | 275.5 | 148.6 |
| Per share (diluted) | $13.42 | $4.88 | $1.66 | $2.76 | $9.42 | $5.92 | $9.85 | $5.31 |