Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net income (loss)	$ 8,318.4	$ 3,232.0	$ (204.1)
Adjustments to Reconcile Net Income (Loss) to Cash Flows from Operating Activities:
Gain related to disposal or sale	(309.8)	0.0	0.0
Depreciation and amortization	1,232.6	1,609.0	1,567.3
Change in deferred income taxes	62.4	326.8	(787.9)
Stock-based compensation expense	312.4	279.5	281.3
Acquired in-process research and development (Note 3)	239.6	1,983.9	1,112.6
Other non-cash operating activities, net	348.7	472.0	441.5
Other changes in operating assets and liabilities, net of acquisitions and divestitures:
Receivables—(increase) decrease	(127.2)	(996.7)	(357.0)
Inventories—(increase) decrease	(258.7)	7.8	(253.9)
Other assets—(increase) decrease	(602.3)	(980.0)	(590.1)
Income taxes payable—increase (decrease)	(221.3)	(125.3)	3,489.6
Accounts payable and other liabilities—increase (decrease)	(477.7)	(284.5)	916.3
Net Cash Provided by Operating Activities	4,836.6	5,524.5	5,615.6
Cash Flows from Investing Activities
Purchases of property and equipment	(1,033.9)	(1,210.6)	(1,076.8)
Proceeds from sales and maturities of short-term investments	136.6	2,552.5	4,852.5
Purchases of short-term investments	(42.7)	(112.2)	(3,389.7)
Proceeds from sales of noncurrent investments	609.8	3,509.5	2,586.0
Purchases of noncurrent investments	(247.5)	(837.9)	(4,611.6)
Purchases of in-process research and development	(319.6)	(1,807.6)	(1,086.8)
Cash paid for acquisitions, net of cash acquired (Note 3 and 19)	(6,917.7)	0.0	(882.1)
Other investing activities, net	(248.7)	(187.7)	(175.1)
Net Cash Provided by (Used for) Investing Activities	(8,082.9)	1,906.0	(3,783.6)
Cash Flows from Financing Activities
Dividends paid	(2,409.8)	(2,311.8)	(2,192.1)
Net change in short-term borrowings	995.4	(2,197.9)	1,397.5
Proceeds from issuance of long-term debt	6,556.4	2,477.7	2,232.0
Repayments of long-term debt	(2,866.4)	(1,009.1)	(630.6)
Purchases of common stock	(4,400.0)	(4,150.7)	(299.8)
Net proceeds from Elanco initial public offering (Note 19)	0.0	1,659.7	0.0
Other financing activities, net	(200.1)	(372.8)	(364.4)
Net Cash Provided by (Used for) Financing Activities	(2,324.5)	(5,904.9)	142.6
Effect of exchange rate changes on cash and cash equivalents	(89.9)	(63.6)	(20.5)
Net increase (decrease) in cash and cash equivalents	(5,660.7)	1,462.0	1,954.1
Cash and cash equivalents at beginning of year (includes $677.5 (2019), $324.4 (2018), and $258.8 (2017) of discontinued operations)	7,998.2	6,536.2	4,582.1
Cash and Cash Equivalents at End of Year (includes $677.5 (2018) and $324.4 (2017) of discontinued operations)	2,337.5	7,320.7
Cash and Cash Equivalents at End of Year (includes $677.5 (2018) and $324.4 (2017) of discontinued operations)		7,998.2	6,536.2
Elanco | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Adjustments to Reconcile Net Income (Loss) to Cash Flows from Operating Activities:
Gain related to disposal or sale	(3,680.5)	0.0	0.0
Cash Flows from Investing Activities
Cash distributed to Elanco upon disposition	(374.0)	0.0	0.0
Legacy Antibiotic Medicines and a Manufacturing Facility in Suzhou, China | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Adjustments to Reconcile Net Income (Loss) to Cash Flows from Operating Activities:
Gain related to disposal or sale	(309.8)	0.0	0.0
Cash Flows from Investing Activities
Cash received for sale of antibiotic business in China	$ 354.8	$ 0.0	$ 0.0