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Fair Value Measurements - Narrative (Details) $ in Millions, € in Billions	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2025 EUR (€)
Derivative [Line Items]
Other finance liabilities \| €				€ 4.8
Accumulated other comprehensive loss	$ 848	$ 857
Level 3 \| Carrying Amount \| Variable Interest Entity, Primary Beneficiary \| Factoring and EIP Securitization Arrangement
Derivative [Line Items]
Carrying amounts of deferred purchase price assets	130	148
Interest Expense
Derivative [Line Items]
Amount amortized from AOCI into interest expense	254	236	$ 219
Amount expected to be amortized from AOCI into interest expense over next 12 months	274
Cross-Currency Swap
Derivative [Line Items]
Other finance liabilities \| €				€ 4.8
Amount amortized from AOCI into interest expense	(661)	79
Interest Rate Contract
Derivative [Line Items]
Accumulated other comprehensive loss	$ 771	$ 960