Fair Value Measurements - Carrying Amounts, Estimated Fair Values and Valuation Input Levels of the Company's Debt Instruments, Interest Rate Derivatives and Foreign Currency Contracts (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount [Member] | Prepaid Expenses and Other Current Assets [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Foreign currency contracts	$ 5.5	$ 10.7
Carrying Amount [Member] | Other Accrued Liabilities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Foreign currency contracts	9.4	5.9
Carrying Amount [Member] | Other Noncurrent Liabilities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate swap contracts	33.8	16.3
Fair Value [Member] | Prepaid Expenses and Other Current Assets [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Foreign currency contracts	5.5	10.7
Fair Value [Member] | Other Accrued Liabilities [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Foreign currency contracts	9.4	5.9
Fair Value [Member] | Other Noncurrent Liabilities [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate swap contracts	33.8	16.3
7.125% Senior Notes Due 2028 [Member] | Carrying Amount [Member] | Long Term Debt Noncurrent [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	700.0
7.125% Senior Notes Due 2028 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	722.8
5.00% Senior Notes Due 2027 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	750.0	750.0
5.00% Senior Notes Due 2027 [Member] | Carrying Amount [Member] | Long Term Debt Noncurrent [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	750.0	750.0
5.00% Senior Notes Due 2027 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	720.0	696.4
8.25% Senior Notes Due 2027 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,000.0	1,000.0
8.25% Senior Notes Due 2027 [Member] | Carrying Amount [Member] | Long Term Debt Noncurrent [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,000.0	1,000.0
8.25% Senior Notes Due 2027 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,040.0	1,052.5
6.00% Senior Notes Due 2025 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,400.0	1,500.0
6.00% Senior Notes Due 2025 [Member] | Carrying Amount [Member] | Long Term Debt Noncurrent [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,400.0	1,500.0
6.00% Senior Notes Due 2025 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,415.5	1,501.7
5.50% Senior Notes Due 2024 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes		650.0
5.50% Senior Notes Due 2024 [Member] | Carrying Amount [Member] | Long Term Debt Noncurrent [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes		650.0
5.50% Senior Notes Due 2024 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes		656.0
5.00% Senior Notes Due 2021 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes		150.0
5.00% Senior Notes Due 2021 [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes		150.0
5.00% Senior Notes Due 2021 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes		149.9
6.00% Senior Secured Notes Due 2026 [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior secured debt	1,500.0	1,500.0
6.00% Senior Secured Notes Due 2026 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,560.0	1,595.6
5.50% Senior Secured Notes Due 2024 [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior secured debt	1,250.0	1,250.0
5.50% Senior Secured Notes Due 2024 [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	1,281.6	1,302.1
Senior Secured Term Loan Due 2026 (Member) | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior secured debt	3,168.0	3,192.0
Senior Secured Term Loans Due 2026 (Member) | Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior secured term loans	$ 3,092.8	$ 3,219.9