Revenue

The Company recognizes revenue when performance obligations identified under the terms of contracts with its customers are satisfied, which generally occurs, for products, upon the transfer of control in accordance with the contractual terms and conditions of the sale. The majority of the Company’s revenue associated with products is recognized at a point in time when the product is shipped to the customer, with a relatively small amount of transactions in the Power segment recognized upon delivery of the product at the destination. Revenue from service contracts and post-shipment performance obligations are less than four percent of total annual consolidated net revenue and those service contracts and post-shipment obligations are primarily within the Power segment. Revenue from service contracts and post-shipment performance obligations is recognized when or as those obligations are satisfied. The Company primarily offers assurance-type standard warranties that do not represent separate performance obligations and on occasion will separately offer and price extended warranties that are separate performance obligations for which the associated revenue is recognized over-time based on the extended warranty period. The Company records amounts billed to customers for reimbursement of shipping and handling costs within revenue. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as fulfillment costs and are included in cost of goods sold. Sales taxes and other usage-based taxes are excluded from revenue.

Within the Electrical segment, certain businesses require a portion of the transaction price to be paid in advance of transfer of control. Advance payments are not considered a significant financing component as they are received less than one year before the related performance obligations are satisfied. In addition, in the Power segment, certain businesses offer annual maintenance service contracts that require payment at the beginning of the contract period. These payments are treated as a contract liability and are classified in Other accrued liabilities in the Condensed Consolidated Balance Sheet. Once control transfers to the customer and the Company meets the revenue recognition criteria, the deferred revenue is recognized in the Condensed Consolidated Statement of Income. The deferred revenue relating to the annual maintenance service contracts is recognized in the Condensed Consolidated Statement of Income on a straight-line basis over the expected term of the contract.

The following table presents disaggregated revenue by business group:



	Three Months Ended March 31,
	2019		2018		2019		2018		2019		2018
in millions	Electrical				Power				Total
Net sales
Hubbell Commercial and Industrial	$	221.3	$	215.5	$	—	$	—	$	221.3	$	215.5
Hubbell Construction and Energy	188.4		186.4		—		—		188.4		186.4
Hubbell Lighting	220.5		216.2		—		—		220.5		216.2
Hubbell Power Systems	—		—		457.1		373.1		457.1		373.1
Total net sales	$	630.2	$	618.1	$	457.1	$	373.1	$	1,087.3	$	991.2

The following table presents disaggregated revenue by geographic location (on a geographic basis, the Company defines "international" as operations based outside of the United States and its possessions):



	Three Months Ended March 31,
	2019		2018		2019		2018		2019		2018
in millions	Electrical				Power				Total
Net sales
United States	$	565.7	$	546.7	$	431.2	$	348.4	$	996.9	$	895.1
International	64.5		71.4		25.9		24.7		90.4		96.1
Total net sales	$	630.2	$	618.1	$	457.1	$	373.1	$	1,087.3	$	991.2

Contract Balances

Our contract liabilities consist of advance payments for products as well as deferred revenue on service obligations and extended warranties. The current portion of deferred revenue is included in Other accrued liabilities and the non-current portion of deferred revenue is included in Other non-current liabilities in the Condensed Consolidated Balance Sheet.

Contract liabilities were $32.2 million as of March 31, 2019 compared to $27.7 million as of December 31, 2018. The $4.5 million increase in our contract liabilities balance was primarily due to timing of advance payments on certain orders, partially offset by the recognition of $7.3 million in revenue related to amounts that were recorded in contract liabilities at January 1, 2019. The Company has an immaterial amount of contract assets relating to performance obligations satisfied prior to payment that is recorded in Other long-term assets in the Condensed Consolidated Balance Sheet. Impairment losses recognized on our receivables and contract assets were immaterial in the first quarter of 2019.

Unsatisfied Performance Obligations

As of March 31, 2019, the Company had approximately $500 million of unsatisfied performance obligations for contracts with an original expected length of greater than one year, primarily relating to long-term contracts of the Power segment to deliver and install meters. The Company expects that a majority of the unsatisfied performance obligations will be completed and recognized over the next 3 years.