Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The following table summarizes revenue from contracts with customers by principal service line (in millions):

	Years ended December 31
	2018			2017			2016
Commercial Risk Solutions	$	4,652		$	4,169		$	3,929
Reinsurance Solutions	1,563			1,429			1,361
Retirement Solutions	1,865			1,755			1,707
Health Solutions	1,596			1,515			1,370
Data & Analytic Services	1,105			1,140			1,050
Elimination	(11		)	(10		)	(8		)
Total revenue	$	10,770		$	9,998		$	9,409

Consolidated revenue from contracts with customers by geographic area, which is attributed on the basis of where the services are performed, is as follows (in millions):

	Years ended December 31
	2018		2017		2016
United States	$	4,677	$	4,425	$	3,981
Americas other than United States	940		976		899
United Kingdom	1,555		1,436		1,354
Europe, Middle East, & Africa other than United Kingdom	2,413		2,025		1,760
Asia Pacific	1,185		1,136		1,415
Total revenue	$	10,770	$	9,998	$	9,409

Capitalized Contract Cost

An analysis of the changes in the net carrying amount of costs to obtain contracts with customers is as follows (in millions):

	2018
Balance at beginning of period (1)	$	145
Additions	53
Amortization	(41		)
Impairment	—
Foreign currency translation and other	(1		)
Balance at end of period	$	156

(1) Upon adoption of the new revenue recognition standard on January 1, 2018, Aon capitalized $145 million of costs to obtain contracts with customers.

An analysis of the changes in the net carrying amount of costs to fulfill contracts with customers is as follows (in millions):

	2018
Balance at beginning of period (1)	$	298
Additions	1,504
Amortization	(1,465		)
Impairment	—
Foreign currency translation and other	(8		)
Balance at end of period	$	329

(1) Upon adoption of the new revenue recognition standard on January 1, 2018, Aon capitalized $298 million of costs to fulfill contracts with customers.