Revenue

We disaggregate our revenue from contracts with customers by segment, geographic location and vertical, as we believe these best depict how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. Refer to Note 14 for revenue disaggregated by segment.

Geographic net sales information, based on geographic destination of the sale, was as follows:



	Three months ended
In millions	March 31, 2019		March 31, 2018
U.S.	$	426.0	$	452.4
Western Europe	104.3		110.3
Developing ⁽¹⁾	108.9		113.0
Other Developed ⁽²⁾	49.7		56.9
Consolidated net sales	$	688.9	$	732.6
⁽¹⁾Developing includes China, Eastern Europe, Latin America, the Middle East and Southeast Asia.
⁽²⁾Other Developed includes Australia, Canada and Japan.

Vertical net sales information was as follows:



	Three months ended
In millions	March 31, 2019		March 31, 2018
Residential	$	383.6	$	412.2
Commercial	150.7		151.8
Industrial	154.6		168.6
Consolidated net sales	$	688.9	$	732.6

Performance obligations

On March 31, 2019, we had $66.4 million of remaining performance obligations on contracts with an original expected duration of one year or more. We expect to recognize the majority of our remaining performance obligations on these contracts within the next 12 to 18 months.

Contract assets and liabilities

Contract assets and liabilities consisted of the following:



In millions	March 31, 2019		December 31, 2018		$ Change		% Change
Contract assets	$	38.4	$	36.5	$	1.9	5.2	%
Contract liabilities	32.9		32.8		0.1		0.3	%
Net contract assets	$	5.5	$	3.7	$	1.8	48.6	%

The $1.8 million increase in net contract assets from December 31, 2018 to March 31, 2019 was primarily the result of timing of milestone payments. Approximately 50% of our contract liabilities at December 31, 2018 were recognized in revenue in the first quarter of 2019. There were no impairment losses recognized on our contract assets for the three months ended March 31, 2019.