Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unconditional Purchase Obligation [Line Items]
Purchase Obligation	$ 74,283
Rent expenses for operating leases	95	$ 100	$ 61
Mortgage commitment derivatives
Unconditional Purchase Obligation [Line Items]
Purchase Obligation	$ 74,000