| 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 | 340.7 | 948.6 | -295.7 | 446.9 | 109.5 | -313.1 | 104.2 | 6.5 |
| Depreciation and amortization | 67.9 | 57.8 | 51.8 | 54.5 | 55.0 | 52.2 | 58.4 | 44.9 |
| Asset impairment charges | | | | | | 12.0 | | |
| Stock-based compensation | 188.4 | 183.0 | 177.9 | 166.6 | 148.2 | 133.1 | 96.2 | 69.9 |
| Deferred taxes | 57.1 | -465.6 | -0.4 | -0.4 | -0.5 | | | |
| Change in working capital [+] | 265.9 | -537.8 | 87.1 | -13.0 | -46.5 | -64.2 | 37.3 | -22.0 |
| Accounts receivable | -28.6 | -134.3 | -173.2 | -1.2 | -41.3 | -117.5 | -23.9 | -56.5 |
| Inventories | -67.5 | -21.0 | -19.5 | -6.1 | 4.0 | 4.9 | 4.0 | 0.1 |
| Other current assets | -30.7 | -64.1 | -8.1 | 5.7 | -33.4 | -31.4 | -13.1 | 3.6 |
| Accounts payable | 105.4 | 73.3 | 15.1 | -20.2 | 36.2 | -7.9 | 43.8 | 5.6 |
| Accrued expenses | 220.2 | 131.4 | 113.8 | 79.0 | -12.0 | 87.8 | 26.5 | 25.2 |
| Other | 67.1 | -523.3 | 158.8 | -70.3 | | | | |
| Other operating activities | 50.0 | 563.5 | -145.3 | 56.0 | 70.6 | 87.2 | 8.6 | -9.9 |
| Cash from operations | 969.9 | 749.5 | -124.6 | 710.7 | 336.2 | -93.0 | 304.8 | 89.4 |
| |
| Capital expenditures | -77.8 | -181.0 | -187.4 | -78.1 | -73.5 | -111.0 | -120.3 | -26.0 |
| Purchases of property and equipment | -77.8 | -181.0 | -187.4 | -78.1 | -73.5 | -111.0 | -120.3 | -26.0 |
| Acquisitions | | | | | | | -142.9 | |
| Purchases of short-term investments, net | -0.7 | -3.7 | -3.4 | -9.4 | -4.0 | -115.1 | 30.6 | -39.2 |
| Purchases of short-term investments | -79.9 | -235.2 | -516.9 | -374.8 | -159.9 | -260.8 | -57.4 | -108.2 |
| Sales of short-term investments | 79.2 | 231.5 | 513.5 | 365.4 | 155.9 | 145.7 | 88.0 | 69.0 |
| Other cash from investing | | -23.0 | -78.2 | | -8.9 | -123.9 | | -39.8 |
| Cash from investing | -78.5 | -207.7 | -269.0 | -87.5 | -86.4 | -350.0 | -232.5 | -105.0 |
| |
| Issuance of common stock, net | | | | | | 649.4 | | |
| Other cash from financing | -0.8 | 6.2 | 71.7 | 45.7 | 14.7 | 40.8 | 44.6 | 84.7 |
| Cash from financing | -0.8 | 6.2 | 71.7 | 45.7 | 14.7 | 690.2 | 44.6 | 84.7 |
| |
| Free cash flow | 892.1 | 568.5 | -312.0 | 632.6 | 262.7 | -204.0 | 184.5 | 63.4 |
| Per share (diluted) | $3.98 | $2.56 | ($1.43) | $2.91 | $1.22 | ($1.00) | $0.95 | $0.34 |
| |
| Cash paid for interest | | | | 0.2 | 0.3 | 0.3 | 7.2 | 12.7 |
| Cash paid for income taxes | 136.2 | 67.7 | 70.7 | 33.6 | 5.4 | 6.3 | 0.9 | |