Acquisitions (Details) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended		3 Months Ended											12 Months Ended
		Apr. 30, 2014	Jan. 31, 2017	Jan. 31, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 01, 2015
Amortization of Intangible Assets																$ 687.9	$ 631.8	$ 535.9
Cost of sales					$ 1,466.0	$ 1,400.9	$ 1,465.0	$ 1,323.0	$ 1,389.2	$ 1,236.9	$ 1,218.4	$ 1,192.7				5,654.9	5,037.2	4,932.5
Interest Expense																185.2	161.2	148.8
Restricted cash													$ 5,410.0					5,410.0
Acquired in-process research and development					30.0	$ 0.0	$ 0.0	$ 0.0	199.0	$ 0.0	80.0	256.0				30.0	535.0	200.2
Payments to Acquire Businesses, Net of Cash Acquired																45.0	5,283.1	551.4
Goodwill					3,972.7				4,039.9							3,972.7	4,039.9
Vetmedica Inc.'s U.S. Feline, Canine, and Rabies Vaccine Portfolio [Member] | Subsequent Event [Member]
Business Combination, Consideration Transferred			$ 885.0
CoLucid Pharmaceuticals [Member] | Subsequent Event [Member]
Business Combination, Consideration Transferred			960.0
Acquired in-process research and development			$ 850.0
Business Combination, Consideration Transferred, Per Share			$ 46.50
Innovent Biologics, Inc. [Member]
Acquired in-process research and development												56.0
Hanmi Pharmaceutical Co., Ltd. [Member]
Acquired in-process research and development											50.0
BioNTech AG [Member]
Acquired in-process research and development											$ 30.0
Lohmann Animal Health [Member]
Business Combination, Consideration Transferred		$ 591.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		275.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles, Other Intangible Assets		23.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		339.6
Payments to Acquire Businesses, Net of Cash Acquired		551.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt		39.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		81.9
Goodwill	[1]	251.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent		(92.7)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		$ 51.1
Novartis Animal Health [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				19 years
Business Acquisition, Goodwill, Expected Tax Deductible Amount																			$ 1,000.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory																			380.2
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual																$ 1,020.0
Business Combination, Consideration Transferred				$ 5,280.0
Business Acquisition, Pro Forma Revenue																	19,958.7	20,696.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	[2]																		1,953.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets																			298.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net																			3,012.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment																			199.9
Goodwill	[3]																		2,271.1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent																			(60.1)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other																			422.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other																			(108.7)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities																			(73.0)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net																			$ 5,283.1
Business Acquisition, Pro Forma Net Income (Loss)																	$ 2,518.1	$ 2,127.9
Business Acquisition, Pro Forma Earnings Per Share, Diluted																	$ 2.36	$ 1.98
Immunocore Limited [Member]
Acquired in-process research and development														$ 45.0
Locemia Solutions [Member]
Acquired in-process research and development									149.0
Other Product Acquisition Counterparty [Member]
Acquired in-process research and development									25.0
Halozyme Therapeutics, Inc [Member]
Acquired in-process research and development									$ 25.0
AstraZeneca [Member]
Acquired in-process research and development					$ 30.0									$ 50.0	[4]
Adocia [Member]
Acquired in-process research and development													$ 50.0
Tanezumab [Member]
Acquired in-process research and development												$ 200.0
United States [Member] | U.S. Sentinel Product Line [Member]
Proceeds from Divestiture of Businesses				$ 410.0
Acquisition-related Costs [Member] | Novartis Animal Health [Member]
Interest Expense																		$ 112.0
Fair Value Adjustment to Inventory [Member] | Novartis Animal Health [Member]
Cost of sales																	$ (153.1)	153.1
Amortization of Fair Value Adjusted Intangible Assets [Member] | Novartis Animal Health [Member]
Amortization of Intangible Assets																		$ 104.0

[1] (1) Goodwill associated with this acquisition is not deductible for tax purposes.

[2] (1) These intangible assets, which are being amortized to cost of sales on a straight-line basis over their estimated useful lives, were expected to have a weighted average useful life of 19 years.

[3] (2) The goodwill recognized from this acquisition is attributable primarily to expected synergies from combining the operations of Novartis AH with our legacy animal health business, future unidentified projects and products, and the assembled workforce of Novartis AH. Approximately $1.0 billion of the goodwill associated with this acquisition is deductible for tax purposes.

[4] (3) See Note 4 for additional information on our collaboration with AstraZeneca related to this oral beta-secretase cleaving enzyme (BACE) inhibitor.