Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 165	$ 1,469	$ (1,591)	$ 4,429
Decrease in income before income tax expense	4,090		20,440
Income (loss) before income tax expense	$ (44)	$ 4,049	$ (6,496)	$ 13,941
Effective tax rates	(375.00%)	36.00%	24.00%	32.00%