Note 33 - Employee Benefits - Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) (Detail)	12 Months Ended
	Dec. 31, 2023 EUR (€)
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Domain Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Weighted Average duration of defined benefit obligation in Years	12
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Domain Member] | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Weighted Average duration of defined benefit obligation in Years	11
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Domain Member] | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Weighted Average duration of defined benefit obligation in Years	15
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Domain Member] | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Weighted Average duration of defined benefit obligation in Years	9
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Domain Member] | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Weighted Average duration of defined benefit obligation in Years	10
Actual benefit payments 2023
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	€ 746,000,000
Actual benefit payments 2023 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	498,000,000
Actual benefit payments 2023 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	109,000,000
Actual benefit payments 2023 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	89,000,000
Actual benefit payments 2023 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	50,000,000
Benefits expected to be paid 2024
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	854,000,000
Benefits expected to be paid 2024 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	543,000,000
Benefits expected to be paid 2024 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	154,000,000
Benefits expected to be paid 2024 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	81,000,000
Benefits expected to be paid 2024 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	76,000,000
Benefits expected to be paid 2025
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	843,000,000
Benefits expected to be paid 2025 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	551,000,000
Benefits expected to be paid 2025 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	138,000,000
Benefits expected to be paid 2025 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	83,000,000
Benefits expected to be paid 2025 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	71,000,000
Benefits expected to be paid 2026
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	870,000,000
Benefits expected to be paid 2026 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	568,000,000
Benefits expected to be paid 2026 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	146,000,000
Benefits expected to be paid 2026 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	88,000,000
Benefits expected to be paid 2026 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	68,000,000
Benefits expected to be paid 2027
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	903,000,000
Benefits expected to be paid 2027 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	586,000,000
Benefits expected to be paid 2027 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	160,000,000
Benefits expected to be paid 2027 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	87,000,000
Benefits expected to be paid 2027 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	70,000,000
Benefits expected to be paid 2028
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	937,000,000
Benefits expected to be paid 2028 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	603,000,000
Benefits expected to be paid 2028 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	171,000,000
Benefits expected to be paid 2028 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	92,000,000
Benefits expected to be paid 2028 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	71,000,000
Benefits expected to be paid 2029 to 2033
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	4,974,000,000
Benefits expected to be paid 2029 to 2033 | Germany [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	3,252,000,000
Benefits expected to be paid 2029 to 2033 | UK [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	925,000,000
Benefits expected to be paid 2029 to 2033 | US [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	447,000,000
Benefits expected to be paid 2029 to 2033 | Other [Member]
Benefits Expected to be paid by the Retirement Benefit Plans (Impact on Cashflows) [Line Items]
Benefits Expected to be paid by the Retirement Benefit Plans	€ 350,000,000