Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in the Net Carrying Amount of Goodwill by Operating Segment

The changes in the net carrying amount of goodwill for the years ended December 31, 2021 and 2020, respectively, are as follows (in millions):

Balance as of January 1, 2020	$	8,165
Goodwill related to current year acquisitions	314
Goodwill related to disposals	(3)
Foreign currency translation and other	190
Balance as of December 31, 2020	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434

Schedule of Other Intangible Assets by Asset Class

Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description	Amortization Basis	Estimated Useful Life
Customer-related and contract-based	In line with underlying cash flows	7 to 20 years
Technology and other	Straight-line	5 to 7 years
Tradenames	Straight-line	1 to 3 years

Other intangible assets by asset class are as follows (in millions):

As of December 31	2021						2020
	Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount
Customer-related and contract-based	$	2,289	$	1,848	$	441	$	2,337	$	1,775	$	562
Technology and other	407		357		50		435		358		77
Tradenames (1)	14		13		1		14		13		1
Total	$	2,710	$	2,218	$	492	$	2,786	$	2,146	$	640

(1)In 2020, Aon wrote off $1.0 billion of fully amortized tradenames, including the Hewitt and Benfield tradenames. The company no longer expects to receive economic benefits from these tradenames.

Schedule of Estimated Future Amortization Expense on Intangible Assets

The estimated future amortization for finite-lived intangible assets as of December 31, 2021 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2022	$	100
2023	89
2024	72
2025	59
2026	37
Thereafter	135
Total	$	492