Segment Information - EBITDA Reconciliation to Net Earnings (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Adjusted EBITDA
Adjusted EBITDA	$ 70	$ 61	$ 210	$ 157
Amortization of intangibles	(3)	(3)	(7)	(7)
Depreciation	(13)	(11)	(37)	(33)
Restructuring costs	(1)	(2)	(1)	(4)
Interest expense	(9)	(17)	(27)	(49)
Transaction costs related to an anticipated offering of securities	0	0	(4)	0
Acquisition and divestiture related expenses	0	0	0	0
Foreign exchange	0	1	(1)	1
COVID-19 response costs	(1)	(9)	(6)	(11)
Non-service pension expense	0	0		(2)
Other one-time non-operational events	0	(1)		(3)
Income tax (provision) benefit	(8)	(4)	(31)	(11)
Net earnings	35	15	96	38
AST
Adjusted EBITDA
Depreciation	(5)	(5)	(15)	(14)
NC&C
Adjusted EBITDA
Depreciation	(4)	(3)	(10)	(9)
IMS
Adjusted EBITDA
Depreciation	(4)	(3)	(12)	(10)
Operating Segments | AST
Adjusted EBITDA
Adjusted EBITDA	34	38	99	80
Operating Segments | NC&C
Adjusted EBITDA
Adjusted EBITDA	22	19	72	60
Operating Segments | IMS
Adjusted EBITDA
Adjusted EBITDA	14	3	39	15
Corporate & Eliminations
Adjusted EBITDA
Adjusted EBITDA	$ 0	$ 2	$ 0	$ 2