Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		$ 300,875		$ 300,875		$ 299,181
Mortgage Servicing Rights, Fair Value [Member]
Fees and Commissions, Mortgage Banking and Servicing	[1]	110	$ 108	331	$ 322
Principal Amount Outstanding of Loans Serviced For Third Parties		135,029		135,029		140,801
Unpaid Principal Balance of Outstanding Underlying MSRs Purchased				0	7,000
Principal Amount Sold on Loans Serviced for Third Parties				708	781
Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		141,906		141,906		146,208
Commercial Mortgage Servicing Rights [Member]
Fees and Commissions, Mortgage Banking and Servicing	[2]	6	5	19	20
Principal Amount Outstanding of Loans Serviced		40,116		40,116		34,539
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		7,391		7,391		6,399
Servicing Asset at Amortized Cost		72		72		66
Consumer Portfolio Segment [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		134,515		134,515		139,809
Pillar Financial [Member]
Fees and Commissions, Mortgage Banking and Servicing	[2]	5	$ 3	13	$ 9
Principal Amount Outstanding of Loans Serviced For Third Parties		$ 32,725		$ 32,725		$ 28,140

[1] Recognized in Mortgage-related income in the Consolidated Statements of Income.

[2] Recognized in Commercial real estate-related income in the Consolidated Statements of Income.