Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 3,750	$ 2,720	$ 2,628
Less: Net income attributable to redeemable and nonredeemable noncontrolling interests	55	66	64
Net income attributable to Aon shareholders	3,695	2,654	2,564
Other comprehensive income (loss), net of tax:
Change in fair value of financial instruments	4	72	13
Foreign currency translation adjustments	826	(467)	276
Postretirement benefit obligation	72	23	(40)
Total other comprehensive income (expense)	902	(372)	249
Less: Other comprehensive loss attributable to noncontrolling interests	0	0	(1)
Total other comprehensive income (expense) attributable to Aon shareholders	902	(372)	250
Comprehensive income attributable to Aon shareholders	$ 4,597	$ 2,282	$ 2,814