New Accounting Standard - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018	Jan. 01, 2019
Lessee Disclosure [Abstract]
Lease right-of-use assets	$ 241	$ 241		$ 243
Lease liability	256	256		$ 243
Lease costs	$ 30	103	$ 80
Lease payments		$ 32
Lease weighted-average discount rate	5.60%	5.60%
Lease,weighted average remaining lease term	8 years 6 months	8 years 6 months