Consolidated Comprehensive Income Statement (unaudited) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income		$ 944	$ 965	$ 1,041	$ 2,871	$ 3,018
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments		331	115	(276)	77	(237)
Unrealized gain on assets available-for-sale:
Unrealized gain arising during the period		233	753	63	1,169	589
Reclassification adjustment		(6)	(7)	1	(20)	(5)
Total unrealized gain on assets available-for-sale		227	746	64	1,149	584
Defined benefit plans:
Net (loss) arising during the period		0	0	0	0	(9)
Amortization of prior service credit, net loss and initial obligation included in net periodic benefit cost		20	19	10	57	30
Total defined benefit plans		20	19	10	57	21
Net unrealized gain (loss) on cash flow hedges		8	4	(6)	1	(1)
Total other comprehensive income (loss), net of tax	[1]	586	884	(208)	1,284	367
Total comprehensive income		1,530	1,849	833	4,155	3,385
Net (income) attributable to noncontrolling interests		(7)	(15)	(3)	(4)	(17)
Other comprehensive (income) loss attributable to noncontrolling interests		(2)	0	3	0	1
Comprehensive income applicable to shareholders of The Bank of New York Mellon Corporation		1,521	1,834	833	4,151	3,369
Other comprehensive (loss) income attributable to The Bank of New York Mellon Corporation shareholders		$ 584	$ 884	$ (205)	$ 1,284	$ 368

[1] Other comprehensive income (loss) attributable to The Bank of New York Mellon Corporation shareholders was $584 million for the quarter ended Sept. 30, 2020, $884 million for the quarter ended June 30, 2020, $(205) million for the quarter ended Sept. 30, 2019, $1,284 million for the nine months ended Sept. 30, 2020 and $368 million for the nine months ended Sept. 30, 2019.