Income Taxes (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2021
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits	$ 175	$ 188	$ 113
Income Tax Examination, Penalties and Interest Accrued	1	26
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount			20
Income Tax Examination, Penalties and Interest Expense	2	13	$ 2
Deferred Tax Assets, Tax Deferred Expense	$ 847	718
UNITED KINGDOM
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Deferred Tax Assets, Tax Deferred Expense		$ 220
Tax Benefit Amortization Period	20 years
Forecast [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits				$ 30