Segmental Reporting (by Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Segment reporting, operating income/(loss)
Product sales	$ 1,230.2		$ 1,147.7		$ 2,346.9		$ 2,254.6
Royalties	36.3		56.3		74.8		112.6
Other revenues	8.0		3.8		14.7		12.4
Total revenues	1,274.5		1,207.8		2,436.4		2,379.6
Cost of product sales	175.7		152.5		331.6		310.9
Research and development ("R&D")	260.1	[1]	238.6	[1]	484.3	[1]	458.9	[1]
Selling, general and administrative ("SG&A")	457.6	[1]	511.0	[1]	896.3	[1]	1,011.0	[1]
Goodwill Impairment charge	0		0		198.9		0
Gain on sale of product rights	(4.5)		(3.6)		(11.0)		(10.8)
Reorganization costs	26.4		0		43.9		0
Integration and acquisition costs	17.4		7.1		21.5		12.4
Total operating expenses	932.7		905.6		1,965.5		1,782.4
Operating income/(loss)	341.8		302.2		470.9		597.2
Assets	7,902.9		7,041.0		7,902.9		7,041.0		7,317.2
Long-lived assets	956.0		927.2		956.0		927.2
Capital expenditure on long-lived assets	43.3		36.3		76.2		53.8
Cost of Product Sales
Segment reporting, additional information
Depreciation of assets	10.0		7.0		17.8		14.2
Selling, General and Administrative
Segment reporting, additional information
Other depreciation and amortization	61.9		65.5		124.5		124.7
Research and Development Assets | Research and Development
Segment reporting, additional information
Depreciation of assets	4.3		6.4		8.9		12.8
Specialty Pharmaceuticals
Segment reporting, operating income/(loss)
Product sales	813.2		735.5		1,559.3		1,442.2
Royalties	24.8		45.4		50.3		87.8
Other revenues	4.8		3.6		11.2		11.9
Total revenues	842.8		784.5		1,620.8		1,541.9
Cost of product sales	95.0	[2]	84.8	[3]	180.8	[4]	171.9	[5]
Research and development ("R&D")	181.9	[2]	158.3	[3]	329.3	[4]	289.3	[5]
Selling, general and administrative ("SG&A")	242.2	[2]	311.5	[3]	500.1	[4]	611.6	[5]
Goodwill Impairment charge	0				0
Gain on sale of product rights	(4.5)		(3.6)		(11.0)		(10.8)
Reorganization costs	0						0
Integration and acquisition costs	9.9		2.8		11.8		4.4
Total operating expenses	524.5		553.8		1,011.0		1,066.4
Operating income/(loss)	318.3		230.7		609.8		475.5
Assets	3,058.6		2,534.6		3,058.6		2,534.6
Long-lived assets	117.2	[6],[7]	130.1	[6]	117.2	[6],[7]	130.1	[6]
Capital expenditure on long-lived assets	9.5	[7]	12.1	[6]	16.9	[6]	19.2	[6]
Specialty Pharmaceuticals | IPR&D | Research and Development
Segment reporting, additional information
Impairment of unamortized intangible assets	19.9		27.0		19.9		27.0
Human Genetic Therapies
Segment reporting, operating income/(loss)
Product sales	394.9		359.8		746.8		711.2
Royalties	0		0		0		0
Other revenues	3.2		0.2		3.5		0.5
Total revenues	398.1		360.0		750.3		711.7
Cost of product sales	69.4	[2]	50.7	[3]	130.9	[4]	112.0	[5]
Research and development ("R&D")	70.7	[2]	76.0	[3]	140.3	[4]	162.3	[5]
Selling, general and administrative ("SG&A")	103.3	[2]	95.9	[3]	208.8	[4]	200.4	[5]
Goodwill Impairment charge	0				0
Gain on sale of product rights	0		0		0		0
Reorganization costs	0						0
Integration and acquisition costs	6.6		0		8.0		0
Total operating expenses	250.0		222.6		488.0		474.7
Operating income/(loss)	148.1		137.4		262.3		237.0
Assets	2,220.2		1,931.1		2,220.2		1,931.1
Long-lived assets	684.2	[6],[7]	707.9	[6]	684.2	[6],[7]	707.9	[6]
Capital expenditure on long-lived assets	13.5	[7]	18.3	[6]	22.8	[6]	26.3	[6]
Regenerative Medicine
Segment reporting, operating income/(loss)
Product sales	22.1		52.4		40.8		101.2
Royalties	0		0		0		0
Other revenues	0		0		0		0
Total revenues	22.1		52.4		40.8		101.2
Cost of product sales	11.3	[2]	17.0	[3]	19.8	[4]	27.0	[5]
Research and development ("R&D")	7.5	[2]	4.3	[3]	14.7	[4]	7.3	[5]
Selling, general and administrative ("SG&A")	47.1	[2]	42.6	[3]	94.9	[4]	84.2	[5]
Goodwill Impairment charge	0				198.9
Gain on sale of product rights	0		0		0		0
Reorganization costs	0						0
Integration and acquisition costs	0.9		4.3		1.7		8.0
Total operating expenses	66.8		68.2		330.0		126.5
Operating income/(loss)	(44.7)		(15.8)		(289.2)		(25.3)
Assets	748.1		980.5		748.1		980.5
Long-lived assets	52.5	[6],[7]	25.0	[6]	52.5	[6],[7]	25.0	[6]
Capital expenditure on long-lived assets	15.0	[7]	0.1	[6]	24.3	[6]	0.1	[6]
All Other Segment
Segment reporting, operating income/(loss)
Product sales	0		0		0		0
Royalties	11.5		10.9		24.5		24.8
Other revenues	0		0		0		0
Total revenues	11.5		10.9		24.5		24.8
Cost of product sales	0	[2]	0	[3]	0.1	[4]	0	[5]
Research and development ("R&D")	0	[2]	0	[3]	0	[4]	0	[5]
Selling, general and administrative ("SG&A")	65.0	[2]	61.0	[3]	92.5	[4]	114.8	[5]
Goodwill Impairment charge					0
Gain on sale of product rights	0		0		0		0
Reorganization costs	26.4				43.9		0
Integration and acquisition costs	0		0		0		0
Total operating expenses	91.4		61.0		136.5		114.8
Operating income/(loss)	(79.9)		(50.1)		(112.0)		(90.0)
Assets	1,876.0		1,594.8		1,876.0		1,594.8
Long-lived assets	102.1	[6],[7]	64.2	[6]	102.1	[6],[7]	64.2	[6]
Capital expenditure on long-lived assets	$ 5.3	[7]	$ 5.8	[6]	$ 12.2	[6]	$ 8.2	[6]

[1] R&D includes intangible asset impairment charges of $19.9 million (2012: $27.0 million) for the three months and six months to June 30, 2013. SG&A costs includes amortization of intangible assets relating to intellectual property rights acquired of $45.8 million for the three months to June 30, 2013 (2012: $51.0 million) and $91.7 million for the six months to June 30, 2013 (2012: $96.6 million).

[2] (1) Depreciation from manufacturing plants ($10.0 million) is included in Cost of product sales; depreciation of research and development assets ($4.3 million) and impairment of IPR&D intangible assets in the SP reporting segment ($19.9 million) is included in Research and development; and all other depreciation and amortization charges ($61.9 million) is included in Selling, general and administrative.

[3] (1) Depreciation from manufacturing plants ($7.0 million) is included in Cost of product sales; depreciation of research and development assets ($6.4 million) and impairment of IPR&D intangible assets in the SP reporting segment ($27.0 million) is included in Research and development; and all other depreciation and amortization charges ($65.5 million) is included in Selling, general and administrative.

[4] (1) Depreciation from manufacturing plants ($17.8 million) is included in Cost of product sales; depreciation of research and development assets ($8.9 million) and impairment of IPR&D intangible assets in the SP reporting segment ($19.9 million) is included in Research and development; and all other depreciation and amortization charges ($124.5 million) is included in Selling, general and administrative.

[5] (1) Depreciation from manufacturing plants ($14.2 million) is included in Cost of product sales; depreciation of research and development assets ($12.8 million) and impairment of IPR&D intangible assets in the SP reporting segment ($27.0 million) is included in Research and development; and all other depreciation and amortization charges ($124.7 million) is included in Selling, general and administrative.

[6] (2) Long-lived assets comprise all non-current assets (excluding goodwill and other intangible assets, deferred contingent consideration assets, deferred tax assets, investments, income tax receivable and financial instruments).

[7] (2) Long-lived assets comprise all non-current assets (excluding goodwill and other intangible assets, deferred contingent consideration assets, deferred tax assets, investments, income tax receivable and financial instruments)