Taxation - Tax Effects of Components of Other Comprehensive Income (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Before tax
Gains/(losses) on equity instruments at fair value through other comprehensive income, Before tax	€ 178	€ 77
Gains/(losses) on cash flow hedges, Before tax	291	87
Remeasurements of defined benefit pension plans, Before tax	2,405	250	€ 381
Currency retranslation gains/(losses), Before tax	1,237	(2,646)
Other comprehensive income, Before tax	4,111	(2,232)
Tax (charge)/credit
Gains/(losses) on equity instruments at fair value through other comprehensive income, Tax (charge)/credit	(12)	1
Gains/(losses) on cash flow hedges, Tax (charge)/credit	(12)	(27)
Remeasurements of defined benefit pension plans, Tax (charge)/credit	(671)	(35)
Currency retranslation gains/(losses),Tax (charge)/credit	(60)	56
Other comprehensive income, Tax (charge)/credit	(755)	(5)
After tax
Gains/(losses) on equity instruments measured at fair value through other comprehensive income	166	78	29
Cash flow hedges	279	60	176
Remeasurement of defined benefit pension plans	1,734	215	353
Currency retranslation gains/(losses), After tax	1,177	(2,590)	€ (15)
Other comprehensive income, After tax	€ 3,356	€ (2,237)

The gains (losses) recognised in other comprehensive income on exchange differences on the translation of financial statements of foreign operations, before tax, before reclassification adjustments. [Refer: Other comprehensive income]

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The amount of income tax relating to amounts recognised in other comprehensive income in relation to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]

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The amount of income tax relating to amounts recognised in other comprehensive income. [Refer: Other comprehensive income]

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The amount of income tax relating to amounts recognised in other comprehensive income in relation to exchange differences on the translation of financial statements of foreign operations. [Refer: Other comprehensive income; Reserve of exchange differences on translation]

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The amount of income tax relating to amounts recognised in other comprehensive income in relation to hedges of investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: Other comprehensive income; Reserve of gains and losses on hedging instruments that hedge investments in equity instruments]

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The amount of income tax relating to amounts recognised in other comprehensive income in relation to remeasurements of defined benefit plans. [Refer: Other comprehensive income; Reserve of remeasurements of defined benefit plans; Defined benefit plans [member]]

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The amount of income and expense (including reclassification adjustments) that is not recognised in profit or loss as required or permitted by IFRSs. [Refer: IFRSs [member]]

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The amount of other comprehensive income, before tax. [Refer: Other comprehensive income]

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The amount of other comprehensive income, before tax, after reclassification adjustments, related to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income, before tax]

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The amount of other comprehensive income, before tax, related to gains (losses) from changes in the fair value of investments in equity instruments that the entity has designated at fair value through other comprehensive income applying paragraph 5.7.5 of IFRS 9. [Refer: Other comprehensive income, before tax]

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The amount of other comprehensive income, before tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]

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The amount of other comprehensive income, net of tax, after reclassification adjustments, related to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]

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The amount of other comprehensive income, net of tax, after reclassification adjustments, related to exchange differences when financial statements of foreign operations are translated. [Refer: Other comprehensive income]

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The amount of other comprehensive income, net of tax, related to gains (losses) from changes in the fair value of investments in equity instruments that the entity has designated at fair value through other comprehensive income applying paragraph 5.7.5 of IFRS 9. [Refer: Other comprehensive income]

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The amount of other comprehensive income, net of tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]

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Other comprehensive income before tax [Abstract].

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Other comprehensive income, net of tax [abstract]

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Other comprehensive income tax [Abstract].

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