Contracts with Customers (Notes)

3 Months Ended

Mar. 31, 2019

Revenue from Contract with Customer [Abstract]

Long-term Contracts or Programs Disclosure [Text Block]

Contracts with Customers

Unbilled receivables increased from $10,025 at December 31, 2018 to $10,208 at March 31, 2019, primarily driven by revenue recognized at BDS and BGS in excess of billings.

Advances and progress billings increased from $50,676 at December 31, 2018 to $52,534 at March 31, 2019, primarily driven by advances on orders received in excess of revenue recognized at BCA, BDS and BGS.

Revenues recognized during the three months ended March 31, 2019 and 2018 from amounts recorded as Advances and progress billings at the beginning of each year were $5,897 and $6,453.