Goodwill and Other Intangible Assets - Estimated Aggregate Pre-Tax Amortization Expense Related to Intangible Assets (Details) $ in Millions	Mar. 31, 2019 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense remainder of 2019	$ 8
Amortization expense 2020	10
Amortization expense 2021	10
Amortization expense 2022	10
Amortization expense 2023	$ 10