Basis of Presentation and Significant Accounting Policies - Summary of Impact of Adoption of Topic 606 on Condensed Consolidated Statement of Operations and Condensed Consolidated Balance Sheet (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Item Effected [Line Items]
Accounts receivable, net	$ 2,015.4		$ 2,015.4			$ 1,879.3
Inventory, net	1,857.5		1,857.5			1,662.4
Prepaid expenses and other	279.6		279.6			327.9
Current assets held for sale	6,612.4		6,612.4			6,894.3
Noncurrent assets held for sale						3,321.7
Other accrued liabilities	1,256.1		1,256.1			1,271.9
Current liabilities held for sale	1,212.7		1,212.7			1,711.3
Noncurrent liabilities held for sale						12.8
Retained earnings (deficit)	(2,694.8)		(2,694.8)			4,611.2
Net sales	2,277.2	$ 2,466.6	6,290.3	$ 7,062.8
Cost of products sold	1,460.2	1,601.7	4,093.2	4,613.6
Selling, general and administrative expenses	575.7	687.9	1,815.6	2,052.7
Operating income (loss)	(7,903.8)	141.1	(7,846.3)	243.8
Income tax benefit	(1,218.0)	(131.1)	(1,251.4)	(99.6)
Loss from continuing operations	(6,795.3)	111.1	(6,926.4)	672.0
Net income (loss)	(7,311.0)	$ 234.4	(7,126.0)	$ 1,095.9
Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Accounts receivable, net	2,015.4		2,015.4		$ 1,979.6	1,879.3
Inventory, net	1,857.5		1,857.5
Prepaid expenses and other	279.6		279.6		342.5	327.9
Current assets held for sale	6,612.4		6,612.4		6,915.6	6,894.3
Noncurrent assets held for sale					3,355.5	3,321.7
Other accrued liabilities	1,256.1		1,256.1		1,386.8	1,271.9
Current liabilities held for sale	1,212.7		1,212.7		1,732.6	1,711.3
Noncurrent liabilities held for sale					46.6	12.8
Retained earnings (deficit)	(2,694.8)		(2,694.8)		$ 4,611.2	4,611.2
Net sales	2,277.2		6,290.3
Cost of products sold	1,460.2		4,093.2
Selling, general and administrative expenses	575.7		1,815.6
Operating income (loss)	(7,903.8)		(7,846.3)
Income tax benefit	(1,218.0)		(1,251.4)
Loss from continuing operations	(6,795.3)		(6,926.4)
Net income (loss)	(7,311.0)		(7,126.0)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Accounts receivable, net	(101.7)		(101.7)			100.3
Inventory, net	0.7		0.7
Prepaid expenses and other	(16.1)		(16.1)			14.6
Current assets held for sale	(39.6)		(39.6)			21.3
Noncurrent assets held for sale						33.8
Other accrued liabilities	(116.4)		(116.4)			114.9
Current liabilities held for sale	(39.6)		(39.6)			21.3
Noncurrent liabilities held for sale						$ 33.8
Retained earnings (deficit)	(0.8)		(0.8)
Net sales	50.8		145.2
Cost of products sold	49.1		139.6
Selling, general and administrative expenses	2.2		6.7
Operating income (loss)	(0.5)		(1.1)
Income tax benefit	0.1		0.3
Loss from continuing operations	(0.4)		(0.8)
Net income (loss)	(0.4)		(0.8)
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Accounts receivable, net	1,913.7		1,913.7
Inventory, net	1,858.2		1,858.2
Prepaid expenses and other	263.5		263.5
Current assets held for sale	6,572.8		6,572.8
Other accrued liabilities	1,139.7		1,139.7
Current liabilities held for sale	1,173.1		1,173.1
Retained earnings (deficit)	(2,695.6)		(2,695.6)
Net sales	2,328.0		6,435.5
Cost of products sold	1,509.3		4,232.8
Selling, general and administrative expenses	577.9		1,822.3
Operating income (loss)	(7,904.3)		(7,847.4)
Income tax benefit	(1,218.1)		(1,251.7)
Loss from continuing operations	(6,795.7)		(6,927.2)
Net income (loss)	$ (7,311.4)		$ (7,126.8)