Summary of Significant Accounting Policies (Details) - USD ($) shares in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Parties [Line Items]
Other assets	$ 13,999,000,000		$ 14,542,000,000	$ 14,312,000,000
Deferred Tax Assets, Net			12,213,000,000	11,910,000,000
Loans held for sale, at lower of cost or fair value	8,103,000,000		6,823,000,000	6,773,000,000
Allowance for Loan and Lease Losses, Real Estate	13,209,000,000	$ 13,232,000,000	10,738,000,000	9,016,000,000	$ 14,203,000,000
Accumulated deficit	$ (119,454,000,000)		(119,915,000,000)	$ (118,776,000,000)
Weighted Average Number of Shares, Contingently Issuable	4,700	4,600
Convertible Preferred Stock, Shares Issued upon Conversion	131
Accounting Standards Update 2016-13 [Member]
Related Parties [Line Items]
Other assets			230,000,000
Deferred Tax Assets, Net			303,000,000
Loans held for sale, at lower of cost or fair value			50,000,000
Allowance for Loan and Lease Losses, Real Estate			1,722,000,000
Accumulated deficit			$ (1,139,000,000)