| 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 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 183.1 | 272.1 |
| Depreciation and amortization | 73.8 | 69.1 | 60.7 | 61.7 | 60.1 | 56.6 | 50.6 | 78.6 |
| Asset impairment charges | | | | | | | | 2.1 |
| Stock-based compensation | 14.1 | 18.6 | 16.8 | 12.7 | 11.9 | 15.2 | 15.4 | 31.7 |
| Deferred taxes | 5.5 | 40.1 | 7.9 | 3.8 | 17.4 | 93.5 | -7.2 | -38.5 |
| Change in working capital [+] | -45.0 | 114.9 | -91.5 | 42.2 | 27.5 | -53.4 | 79.9 | 3.6 |
| Accounts receivable | 15.2 | 84.0 | -98.3 | 15.6 | 37.3 | -34.5 | 28.6 | 40.1 |
| Accounts payable | -40.5 | 28.8 | -1.2 | 44.6 | 1.9 | -7.5 | 19.5 | -24.0 |
| Income taxes | -0.8 | 4.1 | 1.2 | -3.8 | -23.3 | 15.1 | 13.2 | -7.0 |
| Other | -18.9 | -2.0 | 6.8 | -14.1 | 11.6 | -26.6 | 18.5 | -5.5 |
| Other operating activities | 196.3 | 143.3 | 202.6 | 158.9 | 52.4 | 110.1 | -81.7 | -14.5 |
| Cash from operations | 244.7 | 386.0 | 196.4 | 279.4 | 169.3 | 222.0 | 239.9 | 335.2 |
| |
| Capital expenditures [+] | -198.3 | -311.1 | -255.0 | -182.1 | -109.3 | -96.9 | -52.6 | -68.3 |
| Purchases of property and equipment | -198.3 | -311.1 | -255.0 | -182.1 | -109.3 | -96.9 | -52.6 | -68.3 |
| Sales of property and equipment | | | | | | | | 0.1 |
| Acquisitions | -47.3 | | -15.9 | | -213.0 | -0.7 | -117.8 | |
| Sales of short-term investments, net [+] | 3.8 | 5.6 | 6.4 | 5.9 | 3.9 | 13.0 | -0.1 | -7.0 |
| Purchases of short-term investments | | | | | | | -18.6 | -13.5 |
| Sales of short-term investments | 3.8 | 5.6 | 6.4 | 5.9 | 3.9 | 13.0 | 18.5 | 6.5 |
| Other cash from investing | -14.4 | 0.8 | -0.7 | -3.7 | -8.3 | -5.1 | -18.4 | 3.4 |
| Cash from investing | -256.2 | -304.7 | -265.3 | -180.0 | -326.7 | -89.7 | -188.9 | -71.9 |
| |
| Cash dividends paid | -81.1 | -79.7 | -72.9 | -65.4 | -63.8 | -42.0 | -37.4 | -34.5 |
| Repurchase of common stock, net | -20.0 | -225.8 | -22.0 | -20.0 | -214.8 | | -293.0 | -69.7 |
| Option exercises | | | | 4.4 | 3.6 | 17.1 | 18.3 | 7.3 |
| Financing costs | -2.4 | -4.8 | -6.8 | | -9.4 | | -0.7 | -4.9 |
| Other cash from financing | 112.6 | 210.5 | 113.1 | 46.1 | 263.4 | -2.0 | 259.1 | -307.8 |
| Cash from financing | 14.0 | -90.1 | 25.0 | -43.7 | -9.3 | -61.2 | -88.9 | -414.4 |
| |
| Free cash flow | 46.4 | 75.0 | -58.6 | 97.2 | 60.0 | 125.1 | 187.3 | 266.8 |
| Per share (diluted) | $0.51 | $0.79 | ($0.61) | $1.01 | $0.60 | $1.25 | $1.80 | $2.48 |
| |
| Cash paid for interest | 51.3 | 50.8 | 38.3 | 39.7 | 17.0 | 14.3 | 6.5 | 6.6 |
| Cash paid for income taxes | 71.8 | 44.9 | 73.6 | 70.1 | 58.7 | 38.4 | 66.3 | 117.8 |