Financial instruments - fair value - Fair Value of Assets and Liabilities (Details) - GBP (£) £ in Millions | Jun. 30, 2024 | Dec. 31, 2023 |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | £ 312 | £ 333 |
Recurring fair value measurement | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 238 | |
Recurring fair value measurement | Held at fair value through other comprehensive income | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 74 | |
Recurring fair value measurement | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | (57) | |
Recurring fair value measurement | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | (4) | |
Recurring fair value measurement | Payments due to vendors (earnout agreements) | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | (151) | |
Recurring fair value measurement | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 4 | |
Recurring fair value measurement | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 2 | |
Recurring fair value measurement | Level 1 | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 0 | |
Recurring fair value measurement | Level 1 | Held at fair value through other comprehensive income | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 7 | |
Recurring fair value measurement | Level 1 | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | 0 | |
Recurring fair value measurement | Level 1 | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | 0 | |
Recurring fair value measurement | Level 1 | Payments due to vendors (earnout agreements) | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | 0 | |
Recurring fair value measurement | Level 1 | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 0 | |
Recurring fair value measurement | Level 1 | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 0 | |
Recurring fair value measurement | Level 2 | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 0 | |
Recurring fair value measurement | Level 2 | Held at fair value through other comprehensive income | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 0 | |
Recurring fair value measurement | Level 2 | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | (57) | |
Recurring fair value measurement | Level 2 | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | (4) | |
Recurring fair value measurement | Level 2 | Payments due to vendors (earnout agreements) | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | 0 | |
Recurring fair value measurement | Level 2 | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 4 | |
Recurring fair value measurement | Level 2 | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 2 | |
Recurring fair value measurement | Level 3 | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 238 | |
Recurring fair value measurement | Level 3 | Held at fair value through other comprehensive income | | |
Disclosure of detailed information about financial instruments [line items] | | |
Other investments | 67 | |
Recurring fair value measurement | Level 3 | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | 0 | |
Recurring fair value measurement | Level 3 | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | 0 | |
Recurring fair value measurement | Level 3 | Payments due to vendors (earnout agreements) | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative liabilities | (151) | |
Recurring fair value measurement | Level 3 | Derivatives | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | 0 | |
Recurring fair value measurement | Level 3 | Derivatives | Held at fair value through profit or loss | | |
Disclosure of detailed information about financial instruments [line items] | | |
Derivative assets | £ 0 | |