Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Future Minimum Payments Under Operating Leases [Table Text Block]

Lease commitments — Cash obligations under future minimum rental commitments under operating leases and net rental expense at December 31, 2017 are shown in the table below. Operating lease commitments are primarily related to facilities. The significant increase in lease commitments at December 31, 2017 reflects the impact of the acquisitions made during 2017. See also Note 2 for additional information about our acquisitions.

	2018		2019		2020		2021		2022		Thereafter		Total
Lease commitments	$	53	$	48	$	45	$	39	$	31	$	90	$	306

Rent Expense [Table Text Block]

	2017	2016	2015
Rent expense	$61	$50	$49