Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2020
Income Tax Contingency [Line Items]
(Provision) benefit for income taxes	$ (137)	$ 376
Effective income tax rate	20.90%	(23.60%)
Impact (benefit) from restructuring and other corporate matters, depreciation on abandoned technology and other discrete tax items	$ (54)	$ 34
Transfer of intangible assets		$ (768)
Provision for gain on sale of assets	163
Percentage point decrease in effective tax rate		45.80%
Decrease in uncertain tax positions	$ 125
Forecast [Member]
Income Tax Contingency [Line Items]
Tax benefit from changes in UK tax rate			$ (100)