Employee Benefit Plans - Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	$ 129	$ 107	$ 116
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	39	31
Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	85	72
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5	4	$ 4
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	62	52
Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	35	30
Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	27	22
Global return fund
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	19	14
Global return fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	19	14
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	13	14
Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	13	14
Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	12	11
Government bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	12	11
Real estate
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5	4
Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0
Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5	4
LDI (Liability Driven Investment)
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	14	11
LDI (Liability Driven Investment) | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	14	11
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	4	1
Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	$ 4	$ 1