Guarantor Financial Information (Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 472.4	$ 528.8	$ 135.5	$ 2,982.4
Restricted cash	39.4	25.6
Accounts receivable, net	3,009.8	2,616.5
Inventories	3,291.5	3,562.3
Prepaid expenses and other current assets	795.3	806.3
Intercompany receivables	0.0	0.0
Short term intercompany loan receivable	0.0	0.0
Total current assets	7,608.4	7,539.5
Investments	241.1	191.6
Property, plant and equipment (PP&E), net	6,635.4	6,469.6
Goodwill	19,831.7	17,888.2	4,147.8
Intangible assets, net	33,046.1	34,697.5	9,173.3
Deferred tax asset	188.8	96.7
Long term intercompany loan receivable	0.0	0.0
Other non-current assets	205.4	152.3
Total assets	67,756.9	67,035.4
Current liabilities:
Accounts payable and accrued expenses	4,184.5	4,312.4
Short term borrowings and capital leases	2,788.7	3,068.0
Intercompany payables	0.0	0.0
Short term intercompany loan payable	0.0	0.0
Other current liabilities	908.8	362.9
Total current liabilities	7,882.0	7,743.3
Long term borrowings and capital leases	16,752.4	19,899.8
Deferred tax liability	4,748.2	8,322.7
Long term intercompany loan payable	0.0	0.0
Other non-current liabilities	2,197.9	2,121.6
Total liabilities	31,580.5	38,087.4
Total equity	36,176.4	28,948.0	9,829.1	8,662.9
Total liabilities and equity	67,756.9	67,035.4
Eliminations
Current assets:
Cash and cash equivalents	0.0	0.0	0.0	0.0
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	0.0	0.0
Intercompany receivables	(4,802.5)	(5,274.9)
Short term intercompany loan receivable	(2,006.3)	(2,594.8)
Total current assets	(6,808.8)	(7,869.7)
Investments	(94,947.2)	(82,680.5)
Property, plant and equipment (PP&E), net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Deferred tax asset	(304.1)	(273.0)
Long term intercompany loan receivable	(13,659.5)	(14,911.7)
Other non-current assets	0.0	0.0
Total assets	(115,719.6)	(105,734.9)
Current liabilities:
Accounts payable and accrued expenses	0.0	0.0
Short term borrowings and capital leases	0.0	0.0
Intercompany payables	(4,802.5)	(5,274.9)
Short term intercompany loan payable	(2,006.3)	(2,594.8)
Other current liabilities	0.0	0.0
Total current liabilities	(6,808.8)	(7,869.7)
Long term borrowings and capital leases	0.0	0.0
Deferred tax liability	(304.1)	(273.0)
Long term intercompany loan payable	(13,659.5)	(14,911.7)
Other non-current liabilities	0.0	0.0
Total liabilities	(20,772.4)	(23,054.4)
Total equity	(94,947.2)	(82,680.5)
Total liabilities and equity	(115,719.6)	(105,734.9)
Shire plc (Parent Guarantor)
Current assets:
Cash and cash equivalents	0.0	0.0	0.0	0.0
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	0.0	1.8
Intercompany receivables	0.0	0.0
Short term intercompany loan receivable	0.0	0.0
Total current assets	0.0	1.8
Investments	43,204.3	35,656.1
Property, plant and equipment (PP&E), net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Deferred tax asset	0.0	0.0
Long term intercompany loan receivable	0.0	0.0
Other non-current assets	0.0	3.9
Total assets	43,204.3	35,661.8
Current liabilities:
Accounts payable and accrued expenses	0.2	1.3
Short term borrowings and capital leases	0.0	450.0
Intercompany payables	3,585.3	5,247.1
Short term intercompany loan payable	0.0	0.0
Other current liabilities	573.5	0.0
Total current liabilities	4,159.0	5,698.4
Long term borrowings and capital leases	0.0	0.0
Deferred tax liability	0.0	0.0
Long term intercompany loan payable	2,868.9	610.1
Other non-current liabilities	0.0	405.3
Total liabilities	7,027.9	6,713.8
Total equity	36,176.4	28,948.0
Total liabilities and equity	43,204.3	35,661.8
Baxalta Inc. (Baxalta Notes Subsidiary Issuer and SAIIDAC Notes Subsidiary Guarantor)
Current assets:
Cash and cash equivalents	0.5	41.7	0.0	0.0
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	95.2	97.1
Intercompany receivables	0.0	0.0
Short term intercompany loan receivable	0.0	0.0
Total current assets	95.7	138.8
Investments	38,924.6	34,644.2
Property, plant and equipment (PP&E), net	7.6	27.4
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Deferred tax asset	304.1	273.0
Long term intercompany loan receivable	1,609.3	480.7
Other non-current assets	0.0	33.8
Total assets	40,941.3	35,597.9
Current liabilities:
Accounts payable and accrued expenses	18.1	20.0
Short term borrowings and capital leases	748.8	0.0
Intercompany payables	1,217.2	27.8
Short term intercompany loan payable	0.0	0.0
Other current liabilities	10.7	64.6
Total current liabilities	1,994.8	112.4
Long term borrowings and capital leases	4,308.9	5,063.6
Deferred tax liability	0.0	0.0
Long term intercompany loan payable	0.0	0.0
Other non-current liabilities	70.0	61.8
Total liabilities	6,373.7	5,237.8
Total equity	34,567.6	30,360.1
Total liabilities and equity	40,941.3	35,597.9
Non-Guarantor Non-Issuer Subsidiaries
Current assets:
Cash and cash equivalents	471.9	487.1	135.5	2,982.4
Restricted cash	39.4	25.6
Accounts receivable, net	3,009.8	2,616.5
Inventories	3,291.5	3,562.3
Prepaid expenses and other current assets	698.5	707.4
Intercompany receivables	4,682.3	5,154.4
Short term intercompany loan receivable	0.0	0.0
Total current assets	12,193.4	12,553.3
Investments	13,059.4	12,571.8
Property, plant and equipment (PP&E), net	6,627.8	6,442.2
Goodwill	19,831.7	17,888.2
Intangible assets, net	33,046.1	34,697.5
Deferred tax asset	188.8	96.7
Long term intercompany loan receivable	0.0	0.0
Other non-current assets	202.6	114.6
Total assets	85,149.8	84,364.3
Current liabilities:
Accounts payable and accrued expenses	4,080.3	4,205.4
Short term borrowings and capital leases	33.6	23.2
Intercompany payables	0.0	0.0
Short term intercompany loan payable	2,006.3	2,594.8
Other current liabilities	324.6	298.3
Total current liabilities	6,444.8	7,121.7
Long term borrowings and capital leases	393.3	405.2
Deferred tax liability	5,052.3	8,595.7
Long term intercompany loan payable	10,790.6	14,301.6
Other non-current liabilities	2,127.9	1,654.5
Total liabilities	24,808.9	32,078.7
Total equity	60,340.9	52,285.6
Total liabilities and equity	85,149.8	84,364.3
Non-Guarantor Subsidiaries of Baxalta Notes
Current assets:
Cash and cash equivalents	471.9	487.1	135.5	2,982.4
Restricted cash	39.4	25.6
Accounts receivable, net	3,009.8	2,616.5
Inventories	3,291.5	3,562.3
Prepaid expenses and other current assets	700.1	707.4
Intercompany receivables	4,802.5	5,274.9
Short term intercompany loan receivable	2,006.3	2,594.8
Total current assets	14,321.5	15,268.6
Investments	13,059.4	12,571.8
Property, plant and equipment (PP&E), net	6,627.8	6,442.2
Goodwill	19,831.7	17,888.2
Intangible assets, net	33,046.1	34,697.5
Deferred tax asset	188.8	96.7
Long term intercompany loan receivable	12,050.2	14,431.0
Other non-current assets	205.4	114.6
Total assets	99,330.9	101,510.6
Current liabilities:
Accounts payable and accrued expenses	4,166.2	4,291.1
Short term borrowings and capital leases	2,039.9	2,618.0
Intercompany payables	0.0	0.0
Short term intercompany loan payable	2,006.3	2,594.8
Other current liabilities	324.6	298.3
Total current liabilities	8,537.0	9,802.2
Long term borrowings and capital leases	12,443.5	14,836.2
Deferred tax liability	5,052.3	8,595.7
Long term intercompany loan payable	10,790.6	14,301.6
Other non-current liabilities	2,127.9	1,654.5
Total liabilities	38,951.3	49,190.2
Total equity	60,379.6	52,320.4
Total liabilities and equity	99,330.9	101,510.6
SAIIDAC (SAIIDAC Notes Subsidiary Issuer)
Current assets:
Cash and cash equivalents	0.0	0.0	$ 0.0	$ 0.0
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	1.6	0.0
Intercompany receivables	120.2	120.5
Short term intercompany loan receivable	2,006.3	2,594.8
Total current assets	2,128.1	2,715.3
Investments	0.0	0.0
Property, plant and equipment (PP&E), net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Deferred tax asset	0.0	0.0
Long term intercompany loan receivable	12,050.2	14,431.0
Other non-current assets	2.8	0.0
Total assets	14,181.1	17,146.3
Current liabilities:
Accounts payable and accrued expenses	85.9	85.7
Short term borrowings and capital leases	2,006.3	2,594.8
Intercompany payables	0.0	0.0
Short term intercompany loan payable	0.0	0.0
Other current liabilities	0.0	0.0
Total current liabilities	2,092.2	2,680.5
Long term borrowings and capital leases	12,050.2	14,431.0
Deferred tax liability	0.0	0.0
Long term intercompany loan payable	0.0	0.0
Other non-current liabilities	0.0	0.0
Total liabilities	14,142.4	17,111.5
Total equity	38.7	34.8
Total liabilities and equity	$ 14,181.1	$ 17,146.3