Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 1,217.5	$ 1,331.2
Marketable securities	1,320.0	1,278.9
Accounts receivable, net	1,854.3	1,913.8
Due from anti-CD20 therapeutic programs	369.8	413.5
Inventory	1,171.8	1,068.6
Other current assets	786.1	881.1
Total current assets	6,719.5	6,887.1
Marketable securities	821.9	772.1
Property, plant and equipment, net	3,438.3	3,411.5
Operating lease assets	414.5	433.3
Intangible assets, net	2,988.1	3,084.3
Goodwill	5,763.1	5,762.1
Deferred tax asset	1,286.3	1,369.5
Investments and other assets	2,423.0	2,899.0
Total assets	23,854.7	24,618.9
Current liabilities:
Taxes payable	143.1	142.0
Accounts payable	430.4	454.9
Accrued expense and other	2,592.3	3,145.3
Total current liabilities	3,165.8	3,742.2
Notes payable	7,267.2	7,426.2
Deferred tax liability	966.7	1,032.8
Long-term operating lease liabilities	380.0	402.0
Other long-term liabilities	1,411.8	1,329.6
Total liabilities	13,191.5	13,932.8
Commitments and contingencies
Biogen Idec Inc. shareholders' equity
Preferred stock, par value $0.001 per share	0.0	0.0
Common stock, par value $0.0005 per share	0.1	0.1
Additional paid-in capital	0.0	0.0
Accumulated other comprehensive loss	(174.3)	(299.0)
Retained earnings	13,833.5	13,976.3
Treasury stock, at cost	(2,977.1)	(2,977.1)
Total Biogen Inc. shareholders’ equity	10,682.2	10,700.3
Noncontrolling interests	(19.0)	(14.2)
Total equity	10,663.2	10,686.1
Total liabilities and equity	$ 23,854.7	$ 24,618.9