Agreements and Transactions with Baxter (Narrative) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Agreements and Transactions by Party [Line Items]
Selling, general and administrative	$ 3,530,900,000	$ 3,015,200,000	$ 1,842,500,000
Inventories	3,291,500,000	3,562,300,000
Prepaid expenses and other current assets	795,300,000	806,300,000
Other current liabilities	908,800,000	362,900,000
Prepaid expenses and other current assets related indemnification liabilities	103,100,000	189,000,000
Other current liabilities	63,200,000	72,000,000
Other non-current liabilities	59,600,000	92,000,000
Manufacturing and Supply Agreement with Baxter
Agreements and Transactions by Party [Line Items]
Revenue	137,300,000	81,000,000
Selling, general and administrative	52,300,000	54,000,000
Operations Not Yet Transferred To Baxalta
Agreements and Transactions by Party [Line Items]
Revenue	0	101,000,000
Inventories	$ 0	11,000,000
Prepaid expenses and other current assets		50,000,000
Other current liabilities		$ 3,000,000