Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net income	$ 284	$ 9	$ 602	$ 386
Other comprehensive income (loss):
Fair market value adjustment on cash flow hedges, net of income tax (provision) benefit of $0 million, ($1 million), $0 million and $2 million	0	3	1	(5)
Unrealized gain on defined benefit pension plans, net of income tax provision of $0 million	0	0	1	0
Foreign currency translation	213	182	51	(456)
Total other comprehensive income (loss)	215	190	57	(453)
Comprehensive income (loss)	499	199	659	(67)
Less: net income (loss) attributable to noncontrolling interests and redeemable noncontrolling interests	15	7	29	(8)
Less: other comprehensive income (loss) attributable to noncontrolling interests	2	23	(7)	11
Comprehensive income (loss) attributable to Fiserv, Inc.	482	169	637	(70)
Cost of Services
Other comprehensive income (loss):
Reclassification adjustment for net realized (gains) losses on cash flow hedges	(2)	1	(4)	0
Interest Expense
Other comprehensive income (loss):
Reclassification adjustment for net realized (gains) losses on cash flow hedges	$ 4	$ 4	$ 8	$ 8