Guarantor Financial Information (Consolidating Statements of Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Product sales	$ 3,637.1	$ 3,412.3
Royalties and other revenues	128.6	160.0
Total revenues	3,765.7	3,572.3
Costs and expenses:
Cost of sales	1,132.4	1,327.0
Research and development	405.2	379.3
Selling, general and administrative	804.8	888.9
Amortization of acquired intangible assets	484.0	364.0
Integration and acquisition costs	239.7	116.0
Reorganization costs	5.3	5.5
Gain/(loss) on sale of product rights	0.0	(5.5)
Total operating expenses	3,071.4	3,075.2
Operating income from continuing operations	694.3	497.1
Interest income/(expense), net	(124.4)	(139.2)
Other income/(expense), net	23.2	4.5
Total other expense, net	(101.2)	(134.7)
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	593.1	362.4
Income taxes	(43.3)	(6.8)
Equity in income/(losses) of equity method investees, net of taxes	0.8	(0.8)
Income from continuing operations, net of taxes	550.6	354.8
Gain from discontinued operations, net of taxes	0.0	20.2
Net income	550.6	375.0
Comprehensive income/(loss)	1,021.7	645.5
Eliminations
Revenues:
Product sales	0.0	0.0
Royalties and other revenues	0.0	0.0
Total revenues	0.0	0.0
Costs and expenses:
Cost of sales	0.0	0.0
Research and development	0.0	0.0
Selling, general and administrative	0.0	0.0
Amortization of acquired intangible assets	0.0	0.0
Integration and acquisition costs	0.0	0.0
Reorganization costs	0.0	0.0
Gain/(loss) on sale of product rights		0.0
Total operating expenses	0.0	0.0
Operating income from continuing operations	0.0	0.0
Interest income/(expense), net	0.0	0.0
Other income/(expense), net	0.0	0.0
Total other expense, net	0.0	0.0
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	0.0	0.0
Income taxes	0.0	0.0
Equity in income/(losses) of equity method investees, net of taxes	(691.5)	(291.0)
Income from continuing operations, net of taxes	(691.5)	(291.0)
Gain from discontinued operations, net of taxes		0.0
Net income	(691.5)	(291.0)
Comprehensive income/(loss)	(1,662.7)	(806.8)
Shire plc (Parent Guarantor)
Revenues:
Product sales	0.0	0.0
Royalties and other revenues	0.0	0.0
Total revenues	0.0	0.0
Costs and expenses:
Cost of sales	0.0	0.0
Research and development	0.0	0.0
Selling, general and administrative	11.9	14.0
Amortization of acquired intangible assets	0.0	0.0
Integration and acquisition costs	4.4	0.0
Reorganization costs	0.0	0.0
Gain/(loss) on sale of product rights		0.0
Total operating expenses	16.3	14.0
Operating income from continuing operations	(16.3)	(14.0)
Interest income/(expense), net	(32.3)	(30.3)
Other income/(expense), net	(0.6)	0.0
Total other expense, net	(32.9)	(30.3)
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	(49.2)	(44.3)
Income taxes	0.9	1.5
Equity in income/(losses) of equity method investees, net of taxes	598.9	417.8
Income from continuing operations, net of taxes	550.6	375.0
Gain from discontinued operations, net of taxes		0.0
Net income	550.6	375.0
Comprehensive income/(loss)	1,021.7	645.5
SAIIDAC (SAIIDAC Notes Subsidiary Issuer)
Revenues:
Product sales	0.0	0.0
Royalties and other revenues	0.0	0.0
Total revenues	0.0	0.0
Costs and expenses:
Cost of sales	0.0	0.0
Research and development	0.0	0.0
Selling, general and administrative	0.0	0.0
Amortization of acquired intangible assets	0.0	0.0
Integration and acquisition costs	0.0	0.0
Reorganization costs	0.0	0.0
Gain/(loss) on sale of product rights		0.0
Total operating expenses	0.0	0.0
Operating income from continuing operations	0.0	0.0
Interest income/(expense), net	(4.4)	5.4
Other income/(expense), net	0.0	0.0
Total other expense, net	(4.4)	5.4
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	(4.4)	5.4
Income taxes	1.1	(1.3)
Equity in income/(losses) of equity method investees, net of taxes	0.0	0.0
Income from continuing operations, net of taxes	(3.3)	4.1
Gain from discontinued operations, net of taxes		0.0
Net income	(3.3)	4.1
Comprehensive income/(loss)	(3.3)	4.1
Baxalta Inc. (Baxalta Notes Subsidiary Issuer and SAIIDAC Notes Subsidiary Guarantor)
Revenues:
Product sales	0.0	0.0
Royalties and other revenues	0.0	0.0
Total revenues	0.0	0.0
Costs and expenses:
Cost of sales	0.0	1.2
Research and development	0.0	0.0
Selling, general and administrative	2.9	5.7
Amortization of acquired intangible assets	0.0	0.0
Integration and acquisition costs	2.1	25.6
Reorganization costs	0.0	0.0
Gain/(loss) on sale of product rights		0.0
Total operating expenses	5.0	32.5
Operating income from continuing operations	(5.0)	(32.5)
Interest income/(expense), net	(21.3)	(21.4)
Other income/(expense), net	2.0	0.5
Total other expense, net	(19.3)	(20.9)
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	(24.3)	(53.4)
Income taxes	4.4	(19.9)
Equity in income/(losses) of equity method investees, net of taxes	92.6	(126.8)
Income from continuing operations, net of taxes	72.7	(200.1)
Gain from discontinued operations, net of taxes		0.0
Net income	72.7	(200.1)
Comprehensive income/(loss)	572.8	48.7
Non-Guarantor Non-Issuer Subsidiaries
Revenues:
Product sales	3,637.1	3,412.3
Royalties and other revenues	128.6	160.0
Total revenues	3,765.7	3,572.3
Costs and expenses:
Cost of sales	1,132.4	1,325.8
Research and development	405.2	379.3
Selling, general and administrative	790.0	869.2
Amortization of acquired intangible assets	484.0	364.0
Integration and acquisition costs	233.2	90.4
Reorganization costs	5.3	5.5
Gain/(loss) on sale of product rights		(5.5)
Total operating expenses	3,050.1	3,028.7
Operating income from continuing operations	715.6	543.6
Interest income/(expense), net	(66.4)	(92.9)
Other income/(expense), net	21.8	4.0
Total other expense, net	(44.6)	(88.9)
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	671.0	454.7
Income taxes	(49.7)	12.9
Equity in income/(losses) of equity method investees, net of taxes	0.8	(0.8)
Income from continuing operations, net of taxes	622.1	466.8
Gain from discontinued operations, net of taxes		20.2
Net income	622.1	487.0
Comprehensive income/(loss)	1,093.2	754.0
Non-Guarantor Subsidiaries of Baxalta Notes
Revenues:
Product sales	3,637.1	3,412.3
Royalties and other revenues	128.6	160.0
Total revenues	3,765.7	3,572.3
Costs and expenses:
Cost of sales	1,132.4	1,325.8
Research and development	405.2	379.3
Selling, general and administrative	790.0	869.2
Amortization of acquired intangible assets	484.0	364.0
Integration and acquisition costs	233.2	90.4
Reorganization costs	5.3	5.5
Gain/(loss) on sale of product rights		(5.5)
Total operating expenses	3,050.1	3,028.7
Operating income from continuing operations	715.6	543.6
Interest income/(expense), net	(70.8)	(87.5)
Other income/(expense), net	21.8	4.0
Total other expense, net	(49.0)	(83.5)
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	666.6	460.1
Income taxes	(48.6)	11.6
Equity in income/(losses) of equity method investees, net of taxes	0.8	(0.8)
Income from continuing operations, net of taxes	618.8	470.9
Gain from discontinued operations, net of taxes		20.2
Net income	618.8	491.1
Comprehensive income/(loss)	$ 1,089.9	$ 758.1