Basis of Presentation and Significant Accounting Policies - Summary of Impact of Adoption of Topic 842 on Condensed Consolidated Statement of Operations and Condensed Consolidated Balance Sheet (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017
Assets:
Cash and cash equivalents	$ 465.4		$ 465.4		$ 495.7
Accounts receivable, net	1,872.8		1,872.8		2,055.5
Inventories	1,877.2		1,877.2		1,685.1
Prepaid expenses and other current assets	286.3		286.3		280.7
Current assets held for sale	966.7		966.7		2,264.9
Total current assets	5,468.4		5,468.4		6,781.9
Property, plant and equipment, net	1,057.1		1,057.1		1,153.5
Goodwill	3,687.0		3,687.0		3,692.9
Other intangible assets, net	4,602.3		4,602.3		5,587.4
Deferred income taxes	222.5		222.5		179.7
Other assets	333.3		333.3		327.0
Total assets	16,010.2		16,010.2		17,722.4
Liabilities:
Accounts payable	1,118.5		1,118.5		1,130.2
Accrued compensation	157.3		157.3		167.0
Other accrued liabilities	1,465.8		1,465.8		1,254.7
Short-term debt and current portion of long-term debt	633.9		633.9		318.7
Current liabilities held for sale	308.7		308.7		542.2
Total current liabilities	3,684.2		3,684.2		3,412.8
Long-term debt	5,691.7		5,691.7		6,696.3
Deferred income taxes	759.2		759.2		991.0
Other noncurrent liabilities	1,151.3		1,151.3		1,369.1
Total liabilities	11,841.7		11,841.7		12,469.2
Stockholders’ equity:
Total stockholders’ equity	4,168.5	$ 6,026.2	4,168.5	$ 6,026.2	5,253.2	$ 5,004.6	$ 13,991.2	$ 14,181.3
Total liabilities and stockholders’ equity	16,010.2		16,010.2		17,722.4
Income Statement Classification [Abstract]
Net sales	2,450.6	2,548.7	6,738.5	7,061.1	9,648.8
Cost of products sold	1,639.9	1,633.3	4,483.1	4,605.8	6,292.9
Gross profit	810.7	915.4	2,255.4	2,455.3	3,355.9
Selling, general and administrative expenses	607.7	604.4	1,742.0	1,907.1	2,555.9
Restructuring costs, net	2.9	12.4	21.3	64.1	83.1
Impairment of goodwill, intangibles and other assets	834.9	8,133.7	837.8	8,165.3	8,323.3
Operating loss	(634.8)	(7,835.1)	(345.7)	(7,681.2)	(7,606.4)
Non-operating expenses:
Interest expense, net	74.2	105.6	232.6	342.2	446.3
Loss on extinguishment of debt	29.0	0.0	29.0	0.0	(4.1)
Other expense (income), net	7.0	4.2	30.7	(10.5)	11.0
Loss before income taxes	(745.0)	(7,944.9)	(638.0)	(8,012.9)	(8,045.8)
Income tax expense (benefit)	(291.1)	(1,219.6)	(268.3)	(1,268.1)	(1,392.8)
Loss from continuing operations	(453.9)	(6,725.3)	(369.7)	(6,744.8)	(6,653.0)
Loss from discontinued operations, net of tax	(171.9)	(585.7)	(317.5)	(381.2)	(289.5)
Net loss	$ (625.8)	$ (7,311.0)	$ (687.2)	$ (7,126.0)	$ (6,942.5)
Weighted average common shares outstanding:
Basic (in shares)	423.4	471.0	423.3	481.1	473.7
Diluted (in shares)	423.4	471.0	423.3	481.1	473.7
Basic:
Loss from continuing operations (in USD per share)	$ (1.07)	$ (14.28)	$ (0.87)	$ (14.02)	$ (14.04)
Loss from discontinued operations (in USD per share)	(0.41)	(1.24)	(0.75)	(0.79)	(0.61)
Net loss (in USD per share)	(1.48)	(15.52)	(1.62)	(14.81)	(14.65)
Diluted:
Loss from continuing operations (in USD per share)	(1.07)	(14.28)	(0.87)	(14.02)	(14.04)
Loss from discontinued operations (in USD per share)	(0.41)	(1.24)	(0.75)	(0.79)	(0.61)
Net loss (in USD per share)	$ (1.48)	$ (15.52)	$ (1.62)	$ (14.81)	$ (14.65)
As Previously Reported
Assets:
Cash and cash equivalents					$ 495.7
Accounts receivable, net					1,850.7
Inventories					1,583.1
Prepaid expenses and other current assets					278.0
Current assets held for sale					3,541.3
Total current assets					7,748.8
Property, plant and equipment, net					925.6
Goodwill					2,970.2
Other intangible assets, net					5,579.6
Deferred income taxes					165.2
Other assets					327.0
Total assets					17,716.4
Liabilities:
Accounts payable					1,019.5
Accrued compensation					159.1
Other accrued liabilities					1,182.3
Short-term debt and current portion of long-term debt					318.7
Current liabilities held for sale					650.4
Total current liabilities					3,330.0
Long-term debt					6,696.3
Deferred income taxes					1,041.8
Other noncurrent liabilities					1,370.5
Total liabilities					12,438.6
Stockholders’ equity:
Total stockholders’ equity					5,277.8
Total liabilities and stockholders’ equity					17,716.4
Income Statement Classification [Abstract]
Net sales					8,630.9
Cost of products sold					5,622.1
Gross profit					3,008.8
Selling, general and administrative expenses					2,434.8
Restructuring costs, net					80.5
Impairment of goodwill, intangibles and other assets					8,322.0
Operating loss					(7,828.5)
Non-operating expenses:
Interest expense, net					446.3
Loss on extinguishment of debt					(4.1)
Other expense (income), net					11.2
Loss before income taxes					(8,267.7)
Income tax expense (benefit)					(1,478.1)
Loss from continuing operations					(6,789.6)
Loss from discontinued operations, net of tax					(128.3)
Net loss					$ (6,917.9)
Weighted average common shares outstanding:
Basic (in shares)					473.7
Diluted (in shares)					473.7
Basic:
Loss from continuing operations (in USD per share)					$ (14.33)
Loss from discontinued operations (in USD per share)					(0.27)
Net loss (in USD per share)					(14.60)
Diluted:
Loss from continuing operations (in USD per share)					(14.33)
Loss from discontinued operations (in USD per share)					(0.27)
Net loss (in USD per share)					$ (14.60)
Revision
Assets:
Cash and cash equivalents					$ 0.0
Accounts receivable, net					0.0
Inventories					0.0
Prepaid expenses and other current assets					(2.4)
Current assets held for sale					(6.1)
Total current assets					(8.5)
Property, plant and equipment, net					0.0
Goodwill					0.0
Other intangible assets, net					0.0
Deferred income taxes					14.5
Other assets					0.0
Total assets					6.0
Liabilities:
Accounts payable					0.0
Accrued compensation					0.0
Other accrued liabilities					(0.8)
Short-term debt and current portion of long-term debt					0.0
Current liabilities held for sale					100.4
Total current liabilities					99.6
Long-term debt					0.0
Deferred income taxes					(66.7)
Other noncurrent liabilities					(2.3)
Total liabilities					30.6
Stockholders’ equity:
Total stockholders’ equity					(24.6)
Total liabilities and stockholders’ equity					6.0
Income Statement Classification [Abstract]
Net sales					0.0
Cost of products sold					0.0
Gross profit					0.0
Selling, general and administrative expenses					0.0
Restructuring costs, net					0.0
Impairment of goodwill, intangibles and other assets					0.0
Operating loss					0.0
Non-operating expenses:
Interest expense, net					0.0
Loss on extinguishment of debt					0.0
Other expense (income), net					0.0
Loss before income taxes					0.0
Income tax expense (benefit)					0.0
Loss from continuing operations					0.0
Loss from discontinued operations, net of tax					(24.6)
Net loss					$ (24.6)
Weighted average common shares outstanding:
Basic (in shares)					473.7
Diluted (in shares)					473.7
Basic:
Loss from continuing operations (in USD per share)					$ 0
Loss from discontinued operations (in USD per share)					(0.05)
Net loss (in USD per share)					(0.05)
Diluted:
Loss from continuing operations (in USD per share)					0
Loss from discontinued operations (in USD per share)					(0.05)
Net loss (in USD per share)					$ (0.05)
As Revised
Assets:
Cash and cash equivalents					$ 495.7
Accounts receivable, net					1,850.7
Inventories					1,583.1
Prepaid expenses and other current assets					275.6
Current assets held for sale					3,535.2
Total current assets					7,740.3
Property, plant and equipment, net					925.6
Goodwill					2,970.2
Other intangible assets, net					5,579.6
Deferred income taxes					179.7
Other assets					327.0
Total assets					17,722.4
Liabilities:
Accounts payable					1,019.5
Accrued compensation					159.1
Other accrued liabilities					1,181.5
Short-term debt and current portion of long-term debt					318.7
Current liabilities held for sale					750.8
Total current liabilities					3,429.6
Long-term debt					6,696.3
Deferred income taxes					975.1
Other noncurrent liabilities					1,368.2
Total liabilities					12,469.2
Stockholders’ equity:
Total stockholders’ equity					5,253.2
Total liabilities and stockholders’ equity					17,722.4
Income Statement Classification [Abstract]
Net sales					8,630.9
Cost of products sold					5,622.1
Gross profit					3,008.8
Selling, general and administrative expenses					2,434.8
Restructuring costs, net					80.5
Impairment of goodwill, intangibles and other assets					8,322.0
Operating loss					(7,828.5)
Non-operating expenses:
Interest expense, net					446.3
Loss on extinguishment of debt					(4.1)
Other expense (income), net					11.2
Loss before income taxes					(8,267.7)
Income tax expense (benefit)					(1,478.1)
Loss from continuing operations					(6,789.6)
Loss from discontinued operations, net of tax					(152.9)
Net loss					$ (6,942.5)
Weighted average common shares outstanding:
Basic (in shares)					473.7
Diluted (in shares)					473.7
Basic:
Loss from continuing operations (in USD per share)					$ (14.33)
Loss from discontinued operations (in USD per share)					(0.32)
Net loss (in USD per share)					(14.65)
Diluted:
Loss from continuing operations (in USD per share)					(14.33)
Loss from discontinued operations (in USD per share)					(0.32)
Net loss (in USD per share)					$ (14.65)
Reclassification
Assets:
Cash and cash equivalents					$ 0.0
Accounts receivable, net					204.8
Inventories					102.0
Prepaid expenses and other current assets					5.1
Current assets held for sale					(1,270.3)
Total current assets					(958.4)
Property, plant and equipment, net					227.9
Goodwill					722.7
Other intangible assets, net					7.8
Deferred income taxes					0.0
Other assets					0.0
Total assets					0.0
Liabilities:
Accounts payable					110.7
Accrued compensation					7.9
Other accrued liabilities					73.2
Short-term debt and current portion of long-term debt					0.0
Current liabilities held for sale					(208.6)
Total current liabilities					(16.8)
Long-term debt					0.0
Deferred income taxes					15.9
Other noncurrent liabilities					0.9
Total liabilities					0.0
Stockholders’ equity:
Total stockholders’ equity					0.0
Total liabilities and stockholders’ equity					0.0
Income Statement Classification [Abstract]
Net sales					1,017.9
Cost of products sold					670.8
Gross profit					347.1
Selling, general and administrative expenses					121.1
Restructuring costs, net					2.6
Impairment of goodwill, intangibles and other assets					1.3
Operating loss					222.1
Non-operating expenses:
Interest expense, net					0.0
Loss on extinguishment of debt					0.0
Other expense (income), net					(0.2)
Loss before income taxes					221.9
Income tax expense (benefit)					85.3
Loss from continuing operations					136.6
Loss from discontinued operations, net of tax					(136.6)
Net loss					$ 0.0
Weighted average common shares outstanding:
Basic (in shares)					473.7
Diluted (in shares)					473.7
Basic:
Loss from continuing operations (in USD per share)					$ 0.29
Loss from discontinued operations (in USD per share)					(0.29)
Net loss (in USD per share)					0
Diluted:
Loss from continuing operations (in USD per share)					0.29
Loss from discontinued operations (in USD per share)					(0.29)
Net loss (in USD per share)					$ 0