Goodwill and Other Intangible Assets - Gross Carrying Amount, Accumulated Amortization And Net Carrying Amount Of Other Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,802	$ 4,280
Accumulated Amortization	(1,888)	(2,250)
Net Carrying Amount	1,914	2,030	$ 2,369
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,639	3,104
Accumulated Amortization	(1,329)	(1,718)
Net Carrying Amount	1,310	1,386
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	390	403
Accumulated Amortization	(92)	(87)
Net Carrying Amount	298	316
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	673	673
Accumulated Amortization	(398)	(381)
Net Carrying Amount	275	292
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	100	100
Accumulated Amortization	(69)	(64)
Net Carrying Amount	$ 31	$ 36