Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Operating Loss Carryforwards [Line Items]
Provisional amount of income tax									$ 1,914.0	$ 0.0	$ 0.0
Domestic and Puerto Rican companies contribution									15.00%	70.00%	35.00%
Cash payments of income taxes									$ 246.5	$ 700.6	$ 969.0
Income tax at the U.S. federal statutory tax rate									769.1	1,180.9	976.5
Add (deduct):
International operations, including Puerto Rico									(428.9)	(313.7)	(565.2)
General business credits									(66.8)	(58.3)	(69.2)
Non-deductible acquired IPR&D - CoLucid (Note 3)									300.1	0.0	0.0
Other									(86.0)	(172.5)	39.5
Income taxes	$ 1,941.0	$ 36.0	$ 252.5	$ 172.0	$ 120.2	$ 192.7	$ 196.8	$ 126.7	2,401.5	636.4	$ 381.6
Unrecognized tax benefits that would impact effective tax rate	670.9				382.8				670.9	382.8
Year under examination											2015	2013	2012	2010
Settlements									2.4	171.9	$ 446.2
Income tax (benefit) expense									27.4	(52.5)	$ 13.2
Accruals for the payment of interest and penalties	170.7				134.9				170.7	134.9
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense									3,600.0
Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	692.0								692.0
Operating loss carryforwards	3,210.0								3,210.0
Expiration in 10 Years
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	148.9								148.9
Designated Unusable | Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	101.0								101.0
Designated Unusable | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	129.0								129.0
Designated Unusable | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	313.1								313.1
Deferred tax assets related to state net operating losses	113.2								113.2
Other state carryforwards	2.5								2.5
Expiration within 5 years
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	6.5								6.5
Expiration 5 to 20 Years
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	640.5								640.5
No Expiration
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 2,560.0								$ 2,560.0
Tax Years 2010-2012
Operating Loss Carryforwards [Line Items]
Cash payments of income taxes										150.0
Add (deduct):
Settlements										320.0
Maximum
Add (deduct):
Decrease in unrecognized tax benefits is reasonably possible					$ 140.0					$ 140.0