Income Taxes - Operating Loss and Tax Credit Carryforwards, Foreign, By Expiration Dates (Details) $ in Millions	Dec. 31, 2018 USD ($)
2019 through 2023 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland deferred income tax assets for income tax loss carryforwards	$ 0
2024 through 2028 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland deferred income tax assets for income tax loss carryforwards	0
2029 through 2033 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland deferred income tax assets for income tax loss carryforwards	0
2034 through 2043 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland deferred income tax assets for income tax loss carryforwards	0
Not subject to expiration [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland deferred income tax assets for income tax loss carryforwards	1
2019 through 2023 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland income tax loss carryforwards	0
2024 through 2028 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland income tax loss carryforwards	0
2029 through 2033 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland income tax loss carryforwards	0
2034 through 2043 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland income tax loss carryforwards	0
Not subject to expiration [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland income tax loss carryforwards	8
Related valuation allowance [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
Ireland income tax loss carryforwards	0
Ireland deferred income tax assets for income tax loss carryforwards	$ (1)