The following tables provide disaggregation of revenue from contracts with customers based on service offering for the years ended December 31, 2020, 2019 and 2018. It also shows the amount of revenue that is not subject to ASC 606, but is instead governed by other accounting standards.


	Year Ended December 31, 2020
	Total Revenue		Adjustments for Non-ASC 606 Revenue (6)	Total Revenue from Contracts with Customers
	(Dollars in millions)
IP and Data Services (1)	$	3,587	—	3,587
Transport and Infrastructure (2)	2,615		(703)	1,912
Voice and Collaboration (3)	1,423		—	1,423
Other (4)	100		(8)	92
Affiliate Services (5)	208		(208)	—
Total Revenue	$	7,933	(919)	7,014

Timing of revenue:
Goods transferred at a point in time				$	15
Services performed over time				6,999
Total revenue from contracts with customers				$	7,014


	Year Ended December 31, 2019
	Total Revenue		Adjustments for Non-ASC 606 Revenue (6)	Total Revenue from Contracts with Customers
	(Dollars in millions)
IP and Data Services (1)	$	3,655	—	3,655
Transport and Infrastructure (2)	2,544		(704)	1,840
Voice and Collaboration (3)	1,385		—	1,385
Other (4)	9		(9)	—
Affiliate Services (5)	180		(180)	—
Total Revenue	$	7,773	(893)	6,880

Timing of revenue:
Goods transferred at a point in time				$	—
Services performed over time				6,880
Total revenue from contracts with customers				$	6,880


	Year Ended December 31, 2018
	Total Revenue		Adjustments for Non-ASC 606 Revenue (6)	Total Revenue from Contracts with Customers
	(Dollars in millions)
IP and Data Services (1)	$	3,728	—	3,728
Transport and Infrastructure (2)	2,591		(189)	2,402
Voice and Collaboration (3)	1,413		—	1,413
Other (4)	—		(3)	(3)
Affiliate Services (5)	107		(107)	—
Total Revenue	$	7,839	(299)	7,540

Timing of revenue:
Goods transferred at a point in time				$	—
Services performed over time				7,540
Total revenue from contracts with customers				$	7,540

(1)Gross customer receivables of $728 million and $691 million, net of allowance for credit losses of $45 million and $13 million, as of December 31, 2020 and 2019, respectively.

Contract liabilities are consideration we have received from our customers in advance of providing the goods or services promised in the future. We defer recognizing this consideration until we have satisfied the related performance obligation to the customer. Contract liabilities include recurring services billed one month in advance and installation and maintenance charges that are deferred and recognized over the actual or expected contract term, which typically ranges from one to five years depending on the service. Contract liabilities are included within deferred revenue in our consolidated balance sheets. During the years ended December 31, 2020 and 2019, we recognized $188 million and $175 million, respectively, of revenue that was included in contract liabilities as of January 1, 2020 and January 1, 2019, respectively.

As of December 31, 2020, our estimated revenue expected to be recognized in the future related to performance obligations associated with existing customer contracts that are partially or wholly unsatisfied is approximately $4.0 billion. We expect to recognize approximately 91% of this revenue through 2023, with the balance recognized thereafter.

We do not disclose the value of unsatisfied performance obligations for contracts for which we recognize revenue at the amount to which we have the right to invoice for services performed (for example, uncommitted usage or non-recurring charges associated with professional or technical services to be completed), or contracts that are classified as leasing arrangements that are not subject to ASC 606.


	Year Ended December 31, 2020
	Acquisition Costs		Fulfillment Costs
	(Dollars in millions)
Beginning of period balance	$	79	121
Costs incurred	61		88
Amortization	(62)		(87)
End of period balance	$	78	122


	Year Ended December 31, 2019
	Acquisition Costs		Fulfillment Costs
	(Dollars in millions)
Beginning of period balance	$	64	84
Costs incurred	60		103
Amortization	(45)		(66)
End of period balance	$	79	121

Acquisition costs include commission fees paid to employees as a result of obtaining contracts. Fulfillment costs include third party and internal costs associated with the provision, installation and activation of telecommunications services to customers, including labor and materials consumed for these activities.

Deferred acquisition and fulfillment costs are amortized based on the transfer of services on a straight-line basis over the average expected contract term of approximately 30 months for our business customers. Amortized fulfillment costs are included in cost of services and products and amortized acquisition costs are included in selling, general and administrative expenses in our consolidated statements of operations. The amount of these deferred costs that are anticipated to be amortized in the next twelve months are included in other current assets on our consolidated balance sheets. The amount of deferred costs expected to be amortized beyond twelve months is included in other non-current assets on our consolidated balance sheets. Deferred acquisition and fulfillment costs are assessed for impairment on an annual basis.

•IP and Data Services, which include primarily VPN data networks, Ethernet, IP, video (including our facilities-based video services, CDN services and Vyvx broadcast services) and other ancillary services;

•Transport and Infrastructure, which includes private line (including business data services), wavelength, colocation and data center services, including cloud, hosting and application management solutions, professional services, network security services, dark fiber services and other ancillary services;


	Years Ended December 31,
	2020		2019	2018
	(Dollars in millions)
IP and Data Services	$	3,587	3,655	3,728
Transport and Infrastructure	2,615		2,544	2,591
Voice and Collaboration	1,423		1,385	1,413
Other	100		9	—
Affiliate Services	208		180	107
Total operating revenue	$	7,933	7,773	7,839

The following tables present total assets as of the years ended December 31, 2020 and 2019 as well as operating revenue for the years ended December 31, 2020, 2019 and 2018 by geographic region:


	Total Assets
	As of December 31,
	2020		2019
	(Dollars in millions)
North America	$	23,511	24,144
Europe, Middle East and Africa	3,059		2,842
Latin America	2,006		2,112
Total	$	28,576	29,098


	Revenue
	Years Ended December 31,
	2020		2019	2018
	(Dollars in millions)
North America	$	6,411	6,307	6,358
Europe, Middle East and Africa	785		719	744
Latin America	737		747	737
Total	$	7,933	7,773	7,839

Our operations are integrated into and reported as part of the consolidated segment data of Lumen Technologies. Lumen's chief operating decision maker ("CODM") is our CODM, but reviews our financial information on an aggregate basis only in connection with our quarterly and annual reports that we file with the Securities and Exchange Commission. Consequently, we do not provide our discrete financial information to the CODM on a regular basis. As such, we believe we have one reportable segment.

A relatively small number of customers account for a significant percentage of our revenue. Our top ten customers accounted for approximately 16%, 16% and 20% of our revenue for the years ended December 31, 2020, 2019 and 2018, respectively.