| 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 | 36.9 | -1.4 | -180.4 | 194.3 | 241.8 | 243.5 | 111.9 | 426.3 |
| Depreciation and amortization | 163.8 | 162.9 | 160.6 | 159.1 | 148.5 | 126.8 | 174.1 | 173.3 |
| Stock-based compensation | | 20.9 | 17.5 | 23.1 | 21.0 | 24.4 | 14.9 | 21.0 |
| Deferred taxes | | -19.9 | 15.3 | 4.8 | 64.1 | -1.4 | 3.5 | 40.2 |
| Change in working capital [+] | | 102.0 | 105.7 | -52.2 | -59.2 | 95.2 | 44.6 | -31.9 |
| Accounts receivable | | 37.5 | -47.2 | -8.0 | -53.8 | -7.2 | 27.8 | -35.9 |
| Inventories | | -8.0 | 1.6 | -5.2 | -1.4 | -0.2 | -2.9 | -7.6 |
| Other current assets | | -1.2 | -19.6 | -27.1 | -9.9 | -3.1 | -0.7 | -10.6 |
| Accounts payable | | 57.8 | 94.9 | 22.1 | | | | |
| Other | | 15.9 | 76.1 | -33.9 | 6.0 | 105.7 | 20.4 | 22.2 |
| Other operating activities | -24.8 | 37.0 | 221.1 | -70.6 | -63.6 | -87.1 | 54.0 | -106.0 |
| Cash from operations | 176.0 | 301.5 | 339.9 | 258.6 | 352.6 | 401.4 | 402.9 | 523.0 |
| |
| Capital expenditures [+] | -124.8 | -184.0 | -105.0 | -137.3 | -137.8 | -118.2 | -159.2 | -166.7 |
| Purchases of property and equipment | -124.8 | -184.0 | -105.0 | -137.3 | -137.8 | -118.2 | -159.2 | -166.7 |
| Sales of property and equipment | | | | | | | 17.7 | 52.1 |
| Acquisitions | | -15.0 | -6.6 | -22.1 | -10.5 | -482.9 | -37.8 | -393.7 |
| Sales of short-term investments, net [+] | | 22.4 | -20.3 | -28.6 | 93.7 | -11.6 | -1.1 | 1.8 |
| Purchases of short-term investments | | -74.9 | -596.8 | -137.2 | -82.2 | -125.1 | -212.8 | -205.3 |
| Sales of short-term investments | | 97.4 | 576.5 | 108.5 | 175.9 | 113.5 | 211.7 | 207.1 |
| Other cash from investing | | 21.4 | 56.2 | 645.5 | 340.9 | -8.7 | 65.0 | 203.3 |
| Cash from investing | -124.8 | -155.3 | -75.7 | 457.6 | 286.3 | -621.4 | -115.6 | -303.2 |
| |
| Cash dividends paid | | -34.8 | -34.3 | -35.4 | -140.5 | -139.5 | -140.6 | -150.1 |
| Repurchase of common stock, net | | | | -105.0 | | | -197.3 | -131.7 |
| Other cash from financing | | -295.6 | -201.1 | -529.9 | -604.9 | 507.2 | 108.3 | -296.8 |
| Cash from financing | 0.0 | -330.4 | -235.4 | -670.3 | -745.4 | 367.7 | -229.5 | -578.7 |
| |
| Free cash flow | 51.1 | 117.5 | 234.9 | 121.4 | 214.8 | 283.2 | 243.7 | 356.2 |
| Per share (diluted) | $0.29 | $0.66 | $1.37 | $0.68 | $1.14 | $1.51 | $1.29 | $1.77 |