Long-Term and Other Debt - Maturities of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Face Value	$ 9,407
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	44
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	45
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Three	44
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	4,469
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	1,800
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	3,005
Unamortized deferred financing costs and discount/premium	104
Total long-term debt outstanding	9,303	$ 8,725
Capital Lease Obligations
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	2
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	3
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Three	2
Term Loan \| Secured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	42
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	42
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Three	42
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	3,934
Senior Secured Revolver, maturing 2018 \| Secured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	535
Senior Secured Notes, maturing 2025 \| Secured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	1,250
Senior Unsecured Notes Maturing 2025 [Member] \| Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	550
Senior Secured Euro Notes, maturing 2026 \| Secured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	399
Senior Unsecured Euro Notes, Maturing 2026 \| Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	306
Senior Unsecured Notes, Maturing 2026 [Member] \| Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	1,100
Senior Unsecured Notes, Maturing 2028 [Member] \| Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	700
Senior Unsecured Euro Notes, Maturing 2029 [Member] [Member] \| Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	$ 500

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of long-term debt and lease obligation, including portion classified as current.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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