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LONG-TERM DEBT - Schedule of Group's Debt Comprised (Details) € in Millions, £ in Millions, $ in Millions	6 Months Ended			12 Months Ended
	Jun. 30, 2026 USD ($)	Jun. 30, 2026 GBP (£)	Jun. 30, 2026 EUR (€)	Dec. 31, 2025 USD ($)	Dec. 31, 2025 GBP (£)	Dec. 31, 2025 EUR (€)
Debt Instrument [Line Items]
Outstanding balance	$ 12,060			$ 12,359
Less: unamortized debt issuance costs	(82)			(93)
Total debt	11,978			12,266
Less: current portion of long-term debt	(106)			(109)
Long-term debt	11,872			12,157
GBP First Lien Term Loan A due 2028
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency \| £		£ 1,034			£ 1,034
Outstanding balance	1,371			1,392
EUR First Lien Term Loan A due 2028
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency \| €			€ 380			€ 380
Outstanding balance	434			447
USD First Lien Term Loan A due 2028
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency	166			166
Outstanding balance	166			166
GBP Revolving Credit Facility due 2028
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency \| £		275			400
Outstanding balance	365			538
USD First Lien Term Loan B due 2030
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency	3,817			3,836
Outstanding balance	3,818			3,836
USD First Lien Term Loan B due 2032
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency	1,238			1,244
Outstanding balance	1,238			1,244
EUR Senior Secured Notes due 2029
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency \| €			500			500
Outstanding balance	577			593
USD Senior Secured Notes due 2029
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency	525			525
Outstanding balance	532			532
EUR Senior Secured Notes due 2031
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency \| €			€ 850			€ 850
Outstanding balance	978			1,007
USD Senior Secured Notes due 2031
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency	1,625			1,625
Outstanding balance	1,641			1,649
GBP Senior Secured Notes due 2031
Debt Instrument [Line Items]
Principal outstanding balance in currency of borrowing Local currency \| £		£ 700			£ 700
Outstanding balance	$ 940			$ 955