Contracts with Customers (Notes)

6 Months Ended

Jun. 30, 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 $10,247 at June 30, 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 $52,523 at June 30, 2019, primarily driven by advances on orders received in excess of revenue recognized at BCA, BDS and BGS.

Revenues recognized during the six months ended June 30, 2019 and 2018 from amounts recorded as Advances and progress billings at the beginning of each year were $10,116 and $12,757. Revenues

recognized during the three months ended June 30, 2019 and 2018 from amounts recorded as Advances and progress billings at the beginning of each year were $4,219 and $6,304.