CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 1,521.9	$ 654.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	114.9	103.1
Non-cash compensation expense	209.3	213.7
Other non-cash items, net	(175.8)	110.7
Deferred taxes	118.0	(125.3)
Changes in assets and liabilities:
Increase in Sanofi, trade, and other accounts receivable	(47.1)	(247.5)
Increase in inventories	(233.4)	(168.2)
Decrease in prepaid expenses and other assets	33.8	33.2
Increase in deferred revenue	78.9	129.8
Increase in accounts payable, accrued expenses, and other liabilities	20.9	381.6
Total adjustments	119.5	431.1
Net cash provided by operating activities	1,641.4	1,085.3
Cash flows from investing activities:
Purchases of marketable and other securities	(1,533.5)	(2,189.1)
Sales or maturities of marketable securities	2,843.7	745.9
Capital expenditures	(300.0)	(168.9)
Net cash provided by (used in) investing activities	1,010.2	(1,612.1)
Cash flows from financing activities:
Proceeds from bridge loan facility	1,500.0	0.0
Proceeds from issuance of Common Stock	2,168.0	155.1
Payments in connection with Common Stock tendered for employee tax obligations	(571.6)	(40.5)
Repurchases of Common Stock	(5,373.6)	(10.0)
Net cash (used in) provided by financing activities	(2,277.2)	104.6
Net increase (decrease) in cash, cash equivalents, and restricted cash	374.4	(422.2)
Cash, cash equivalents, and restricted cash at beginning of period	1,630.3	1,480.2
Cash, cash equivalents, and restricted cash at end of period	$ 2,004.7	$ 1,058.0