Business Combinations (Details) $ / shares in Units, shares in Millions, $ in Millions				3 Months Ended		6 Months Ended
	Jun. 03, 2016 USD ($) $ / shares shares	Jan. 22, 2016 USD ($) $ / shares	Feb. 21, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Integration and acquisition costs				$ 363.0	$ (212.4)	$ 454.1	$ (136.7)
Non-current assets:
Goodwill				12,962.4	4,173.3	12,962.4	4,173.3	$ 4,147.8	$ 2,474.9
Pro Forma Information
Post acquisition unwind of inventory fair value adjustment included in consolidated statement of income						293.5	16.3
Baxalta
Business Acquisition [Line Items]
Purchase price paid per share of acquiree, in cash (in USD per share) | $ / shares	$ 18
Cash consideration paid	$ 12,366.7
Acquisition-date fair value of consideration	(32,383.5)
Maximum amount of contingent cash consideration	1,500.0
Integration and acquisition costs				414.5		442.3
Business Combination, Consideration Transferred [Abstract]
Cash paid to shareholders	12,366.7
Fair value of stock issued to shareholders	19,353.2
Fair value of partially vested stock options and RSUs assumed	497.6
Fair Value of contingent consideration payable	166.0
Total Purchase Consideration	$ 32,383.5
Shares issued for acquisition, number of shares | shares	305.2
Current assets:
Cash and cash equivalents	$ 583.2
Accounts receivable,net	1,382.8
Inventories	5,341.1
Other current assets	362.2
Total current assets	7,669.3
Non-current assets:
Property, plant and equipment,net	5,687.7
Investments	128.2
Goodwill	6,106.4
Other non-current assets	103.3
Total assets	47,257.1
Current liabilities:
Accounts payable and other current liabilities	1,509.5
Other current liabilities	15.4
Non-current liabilities:
Long term debt, less current portion	5,424.9
Deferred tax liabilities	6,831.7
Other non-current liabilities	1,092.1
Total liabilities	14,873.6
Fair value of identified assets acquired and liabilities assumed	(32,383.5)
Pro Forma Information
Post acquisition revenues included in consolidated statement of income				580.3		580.3
Post acquisition pre-tax losses included in consolidated statement of income				(419.8)		(419.8)
Post acquisition amortization of intangible assets included in consolidated statement of income				74.1		74.1
Post acquisition unwind of inventory fair value adjustment included in consolidated statement of income				266.0		266.0
Post acquisition integration costs included in consolidated statement of income				272.9		272.9
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
defined benefit pension plans, fair value of assets	358.5
Defined benefit net liability	$ (610.4)
Baxalta | Ordinary Shares
Business Acquisition [Line Items]
Shire shares per Baxalta share	0.4446
Baxalta | ADS
Business Acquisition [Line Items]
Shire shares per Baxalta share	0.1482
Baxalta | Currently marketed products
Business Acquisition [Line Items]
Weighted average amortization period of acquired amortizable intangible assets	30 years
Non-current assets:
Other intangible assets, net	$ 24,550.0
Baxalta | Currently marketed products | Minimum
Business Acquisition [Line Items]
Estimated useful life of intangible assets	11 years
Baxalta | Currently marketed products | Maximum
Business Acquisition [Line Items]
Estimated useful life of intangible assets	38 years
Baxalta | In-Process Research and Development ("IPR&D")
Non-current assets:
Other intangible assets, net	$ 2,940.0
Baxalta | In-Process Research and Development ("IPR&D") | Minimum
Business Acquisition [Line Items]
Discount rate used in determining fair value of acquired in process research and development, low rate	10.00%
Baxalta | In-Process Research and Development ("IPR&D") | Maximum
Business Acquisition [Line Items]
Discount rate used in determining fair value of acquired in process research and development, high rate	11.00%
Baxalta | other contract rights
Non-current assets:
Other intangible assets, net	$ 72.2
Dyax
Business Acquisition [Line Items]
Purchase price paid per share of acquiree, in cash (in USD per share) | $ / shares		$ 37.3
Contingent consideration payable, per share | $ / shares		$ 4
Cash consideration paid		$ 5,934.0
Acquisition-date fair value of consideration		(6,330.0)
Maximum amount of contingent cash consideration		646.0
Integration and acquisition costs				2.0		53.7
Business Combination, Consideration Transferred [Abstract]
Cash paid to shareholders		5,934.0
Fair Value of contingent consideration payable		396.0
Current assets:
Cash and cash equivalents		241.2
Accounts receivable,net		13.3
Inventories		20.2
Other current assets		8.1
Total current assets		282.8
Non-current assets:
Property, plant and equipment,net		5.8
Goodwill		2,727.9
Other non-current assets		28.3
Total assets		7,704.8
Current liabilities:
Accounts payable and other current liabilities		30.0
Other current liabilities		1.7
Non-current liabilities:
Deferred tax liabilities		1,341.7
Other non-current liabilities		1.4
Total liabilities		1,374.8
Fair value of identified assets acquired and liabilities assumed		$ (6,330.0)
Pro Forma Information
Post acquisition revenues included in consolidated statement of income				24.0		34.6
Post acquisition pre-tax losses included in consolidated statement of income				131.9		186.4
Post acquisition amortization of intangible assets included in consolidated statement of income				8.0		14.0
Post acquisition unwind of inventory fair value adjustment included in consolidated statement of income				1.5		2.6
Post acquisition integration costs included in consolidated statement of income				$ 9.3		$ 30.3
Dyax | SHP643
Business Acquisition [Line Items]
Discount rate used in determining fair value of acquired in process research and development, high rate		9.00%
Dyax | KALBITOR
Business Acquisition [Line Items]
Estimated useful life of intangible assets		18 years
Dyax | Currently marketed products
Non-current assets:
Other intangible assets, net		$ 135.0
Dyax | In-Process Research and Development ("IPR&D")
Non-current assets:
Other intangible assets, net		$ 4,100.0
Dyax | Royalty rights
Business Acquisition [Line Items]
Weighted average amortization period of acquired amortizable intangible assets		8 years
Non-current assets:
Other intangible assets, net		$ 425.0
Dyax | Royalty rights | Minimum
Business Acquisition [Line Items]
Estimated useful life of intangible assets		7 years
Dyax | Royalty rights | Maximum
Business Acquisition [Line Items]
Estimated useful life of intangible assets		9 years
NPS Pharma
Business Acquisition [Line Items]
Cash consideration paid			$ 5,219.6
Acquisition-date fair value of consideration			5,219.6
Integration and acquisition costs					$ 47.8		$ 117.7
Business Combination, Consideration Transferred [Abstract]
Cash paid to shareholders			5,219.6
Current assets:
Cash and cash equivalents			41.6
Short term investments			67.0
Accounts receivable,net			33.4
Inventories			89.4
Other current assets			11.1
Total current assets			242.5
Non-current assets:
Property, plant and equipment,net			4.8
Goodwill			1,551.0
Total assets			6,791.3
Current liabilities:
Accounts payable and other current liabilities			75.7
Short-term debt			27.4
Non-current liabilities:
Long term debt, less current portion			78.9
Deferred tax liabilities			1,385.2
Other non-current liabilities			4.5
Total liabilities			1,571.7
Fair value of identified assets acquired and liabilities assumed			5,219.6
NPS Pharma | Currently marketed products
Non-current assets:
Other intangible assets, net			$ 4,640.0
NPS Pharma | Currently marketed products | GATTEX/REVESTIVE
Business Acquisition [Line Items]
Estimated useful life of intangible assets			24 years
NPS Pharma | Currently marketed products | NATPARA/NATPAR
Business Acquisition [Line Items]
Estimated useful life of intangible assets			24 years
NPS Pharma | Royalty rights
Business Acquisition [Line Items]
Weighted average amortization period of acquired amortizable intangible assets			4 years
Non-current assets:
Other intangible assets, net			$ 353.0
NPS Pharma | Royalty rights | Minimum
Business Acquisition [Line Items]
Estimated useful life of intangible assets			4 years
NPS Pharma | Royalty rights | Maximum
Business Acquisition [Line Items]
Estimated useful life of intangible assets			5 years