| 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 | 140.7 | 29.4 | 38.4 | 33.1 |
| Depreciation and amortization | 8.0 | 7.2 | 4.7 | 5.0 | 4.6 | 3.5 | 3.2 | 2.6 |
| Stock-based compensation | | | | | 123.0 | 96.3 | 77.1 | 46.1 |
| Deferred taxes | -18.5 | | | | 6.5 | 191.7 | -1.0 | 0.8 |
| Change in working capital [+] | -269.8 | 278.7 | 51.3 | -35.4 | 54.8 | -23.9 | 8.5 | -19.8 |
| Accounts receivable | | | | | 1.0 | -35.6 | 5.5 | -8.0 |
| Other current assets | | | | | -0.6 | -5.4 | 1.9 | -4.7 |
| Deferred revenues | | | | | 2.1 | 2.0 | -4.0 | 1.9 |
| Other | -269.8 | 278.7 | 51.3 | -35.4 | 52.3 | 15.2 | 5.1 | -9.0 |
| Other operating activities | 313.3 | 651.0 | 373.2 | 239.7 | 61.2 | -63.9 | 105.5 | 79.9 |
| Cash from operations | 33.0 | 937.0 | 429.2 | 209.3 | 390.9 | 233.2 | 231.6 | 142.8 |
| |
| Capital expenditures | 6.0 | 16.4 | 40.7 | 6.5 | -6.9 | -5.6 | -2.9 | -4.0 |
| Purchases of property and equipment | 6.0 | 16.4 | 40.7 | 6.5 | -6.9 | -5.6 | -2.9 | -4.0 |
| Purchases of short-term investments, net | 334.7 | 486.1 | 390.6 | 212.4 | 15.8 | -64.2 | 5.1 | 2.0 |
| Purchases of short-term investments | 334.7 | 486.1 | 390.6 | 212.4 | -184.0 | -179.8 | -120.9 | -158.0 |
| Sales of short-term investments | | | | | 199.8 | 115.6 | 126.0 | 160.0 |
| Other cash from investing | -351.9 | -519.6 | -471.2 | -270.8 | 0.4 | 0.4 | -0.8 | 0.2 |
| Cash from investing | -11.2 | -17.0 | -40.0 | -51.9 | 9.3 | -69.4 | 1.4 | -1.7 |
| |
| Cash dividends paid | 174.7 | 480.0 | 282.9 | 209.2 | -313.8 | -255.7 | -154.7 | -80.9 |
| Repurchase of common stock, net | | | | | -33.8 | -12.5 | -3.3 | -0.1 |
| Option exercises | | | 11.9 | 21.5 | 6.8 | 6.1 | | |
| Other cash from financing | -501.6 | -1,082.5 | -622.8 | -440.4 | 2.7 | 1.7 | | -9.2 |
| Cash from financing | -326.9 | -602.5 | -351.8 | -252.7 | -351.7 | -272.5 | -158.0 | -90.2 |
| |
| Free cash flow | 39.0 | 953.4 | 469.9 | 215.8 | 384.0 | 227.5 | 228.7 | 138.8 |
| Per share (diluted) | $0.55 | $13.93 | $7.74 | $3.89 | $7.57 | $6.04 | $9.43 | $6.50 |
| |
| Cash paid for income taxes | 76.4 | 55.2 | -0.3 | 13.4 | 23.5 | 31.8 | 28.6 | 26.0 |