CONTRACT ASSETS AND LIABILITIES

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Contract assets include unbilled amounts typically resulting from sales under contracts when the percentage-of-completion cost-to-cost method of revenue recognition is utilized and revenue recognized exceeds the amount billed to the customer. Contract liabilities (formerly referred to as customer advances and amounts in excess of costs incurred) include advance payments and billings in excess of revenue recognized. Contract assets and contract liabilities were as follows (in millions):



	September 30, 2018		December 31, 2017
Contract assets	$	9,769	$	7,992
Contract liabilities	6,489		7,028

Contract assets increased $1.8 billion during the nine months ended September 30, 2018, primarily due to the recognition of revenue related to the satisfaction or partial satisfaction of performance obligations during the nine months ended September 30, 2018 for which we have not yet had the right to bill our customers. There were no significant impairment losses related to our contract assets during the quarters and nine months ended September 30, 2018 and September 24, 2017.

Contract liabilities decreased $539 million during the nine months ended September 30, 2018, primarily due to revenue recognized in excess of payments received on these performance obligations. During the quarter and nine months ended September 30, 2018, we recognized $711 million and $3.4 billion of our contract liabilities at December 31, 2017 as revenue. During the quarter and nine months ended September 24, 2017, we recognized $507 million and $2.9 billion of our contract liabilities at December 31, 2016 as revenue.