| 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 | 151.7 | 57.9 | -192.3 | 46.3 | 144.0 | 111.5 | -10.9 | 24.4 |
| Depreciation and amortization [+] | 121.1 | 103.0 | 100.5 | 78.2 | 58.8 | 40.5 | 29.8 | 35.4 |
| Depreciation | 121.1 | 103.0 | 100.5 | 78.2 | 58.8 | 40.5 | 29.8 | 35.4 |
| Stock-based compensation | | | | | | 2.4 | 3.8 | 3.9 |
| Deferred taxes | -49.7 | | 142.5 | -41.6 | -72.5 | | | |
| Change in working capital [+] | -75.2 | -44.9 | 192.2 | -26.4 | -8.9 | -15.8 | -2.0 | -3.7 |
| Restricted cash | | | | | | 0.5 | | |
| Accounts receivable | -13.1 | -36.4 | 25.9 | -19.3 | -13.1 | -15.7 | -4.1 | -1.1 |
| Other | -62.1 | -8.6 | 166.3 | -7.1 | 4.2 | -0.6 | 2.2 | -2.6 |
| Other operating activities | 551.9 | 191.1 | -46.3 | 180.2 | 123.1 | 0.6 | 47.9 | 3.7 |
| Cash from operations | 699.8 | 307.1 | 196.6 | 236.7 | 244.5 | 139.2 | 68.6 | 63.8 |
| |
| Capital expenditures [+] | 0.0 | 0.0 | 0.0 | 0.0 | -4.7 | 0.0 | 0.0 | 0.0 |
| Purchases of property and equipment | | | | | -4.7 | | | |
| Sales of property and equipment | 111.7 | | 38.6 | | 0.4 | | | |
| Other cash from investing | -64.1 | -281.2 | -54.9 | -530.6 | -610.0 | -344.1 | -205.7 | |
| Cash from investing | 47.6 | -281.2 | -16.3 | -530.6 | -614.3 | -344.1 | -205.7 | 0.0 |
| |
| Cash dividends paid | -234.1 | -100.7 | -62.3 | -133.2 | -155.1 | -130.9 | -64.8 | -68.6 |
| Repurchase of common stock, net | -150.6 | -46.0 | -24.0 | | | | | |
| Financing costs | | | | -10.9 | -1.0 | -2.3 | -0.4 | -0.4 |
| Other cash from financing | -383.9 | 141.1 | -78.4 | 397.2 | 522.3 | 348.5 | 210.2 | 33.6 |
| Cash from financing | -768.6 | -5.6 | -164.8 | 274.8 | 368.2 | 219.8 | 145.8 | -34.5 |
| |
| Free cash flow | 699.8 | 307.1 | 196.6 | 236.7 | 239.8 | 139.2 | 68.6 | 63.8 |
| Per share (diluted) | $9.25 | $4.49 | $2.90 | $3.83 | $3.35 | $1.33 | $0.83 | $0.80 |
| |
| Cash paid for interest | 36.9 | 30.8 | 33.1 | 13.8 | 12.4 | 2.6 | 2.0 | 0.7 |
| Cash paid for income taxes | 17.0 | 1.1 | | | | | | |