Condensed Consolidating Supplemental Guarantor Information Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	$ 628	$ 572	$ 752
Expenditures for property, plant and equipment	(91)	(143)	(128)
Proceeds from Sale of property, plant, and equipment	11	3	6
Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties	0	0
Additions to capitalized software	(238)	(170)	(166)
Business acquisitions, net	(203)	(206)	(8)
Proceeds from (payment of) of intercompany notes			0
Payments to Acquire Businesses, Gross			(8)
Investments in equity affiliates	0	0	0
Other investing activities, net	9	(4)	6
Net change in funds held for clients - investing	(15)	0	0
Net Cash Provided by (Used in) Investing Activities	(527)	(520)	(290)
Short term borrowings, net	0	(1)	(4)
Proceeds from Issuance of Secured Debt	750	0	0
Repurchase of Series A Convertible Preferred Stock	(302)	0	0
Proceeds from Issuance of Unsecured Debt	1,000	0	0
Payments on term credit facilities	(761)	(51)	(61)
Repayments of Unsecured Debt	(900)	0	0
Payments on revolving credit facilities	(3,216)	(2,233)	(1,940)
Borrowings on revolving credit facilities	3,535	2,453	1,940
Increase (Decrease) in Client Funds Held	(15)	0	0
Payments for Repurchase of Redeemable Noncontrolling Interest	(3)	0	0
Tax withholding payments on behalf of employees	(29)	(36)	(31)
Proceeds from employee stock plans	16	20	15
Debt issuance costs	(32)	0	0
Payments for Repurchase of Common Stock	(96)	(210)	(350)
Other financing activities	(8)	0	(3)
Dividend distribution to consolidated subsidiaries	0	0	0
Equity contribution	0	0	0
Borrowings (repayments) of intercompany notes	0	0	0
Net Cash Provided by (Used in) Financing Activities	(31)	(58)	(434)
Payments to Noncontrolling Interests			(350)
Net Cash Provided by (Used in) Financing Activities			(434)
Net cash used in discontinued operations operating activities	(24)	(36)	(8)
Effect of Exchange Rate changes on cash and cash equivalents	(6)	(25)	16
Decrease in cash, cash equivalents, and restricted cash	40	(67)	36
Restricted Cash	7	12	6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash	516	476	543	$ 507
Parent Company [Member]
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	498	359	447
Expenditures for property, plant and equipment	(43)	(109)	(87)
Proceeds from Sale of property, plant, and equipment	3	1	0
Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties	352	228
Additions to capitalized software	(195)	(144)	(133)
Business acquisitions, net	(91)	(206)
Proceeds from (payment of) of intercompany notes			230
Payments to Acquire Businesses, Gross			(8)
Investments in equity affiliates	0	(14)	13
Other investing activities, net	9	(4)	2
Net change in funds held for clients - investing	0
Net Cash Provided by (Used in) Investing Activities	35	(248)	17
Short term borrowings, net	0	(1)	(5)
Proceeds from Issuance of Secured Debt	750
Repurchase of Series A Convertible Preferred Stock	(302)
Proceeds from Issuance of Unsecured Debt	1,000
Payments on term credit facilities	(761)	(51)	(56)
Repayments of Unsecured Debt	(900)
Payments on revolving credit facilities	(2,830)	(1,755)	(1,700)
Borrowings on revolving credit facilities	2,900	1,875	1,700
Increase (Decrease) in Client Funds Held	0
Payments for Repurchase of Redeemable Noncontrolling Interest	0
Tax withholding payments on behalf of employees	(29)	(36)	(31)
Proceeds from employee stock plans	16	20	15
Debt issuance costs	(32)
Payments for Repurchase of Common Stock	(96)	(210)
Other financing activities	(5)	0	(1)
Dividend distribution to consolidated subsidiaries	0	0	0
Equity contribution	(84)	(10)	0
Borrowings (repayments) of intercompany notes	(135)	0	0
Net Cash Provided by (Used in) Financing Activities	(508)	(168)
Payments to Noncontrolling Interests			(350)
Net Cash Provided by (Used in) Financing Activities			(428)
Net cash used in discontinued operations operating activities	(22)	(36)	(8)
Effect of Exchange Rate changes on cash and cash equivalents	0	(1)	1
Decrease in cash, cash equivalents, and restricted cash	3	(94)	29
Restricted Cash	0	1	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash	15	12	106	77
Guarantor Subsidiary [Member]
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	(281)	(144)	(168)
Expenditures for property, plant and equipment	0	0	0
Proceeds from Sale of property, plant, and equipment	0	0	0
Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties	330	135
Additions to capitalized software	0	0	0
Business acquisitions, net	0	0
Proceeds from (payment of) of intercompany notes			180
Payments to Acquire Businesses, Gross			0
Investments in equity affiliates	0	10	0
Other investing activities, net	0	0	0
Net change in funds held for clients - investing	0
Net Cash Provided by (Used in) Investing Activities	330	145	180
Short term borrowings, net	0	0	0
Proceeds from Issuance of Secured Debt	0
Repurchase of Series A Convertible Preferred Stock	0
Proceeds from Issuance of Unsecured Debt	0
Payments on term credit facilities	0	0	0
Repayments of Unsecured Debt	0
Payments on revolving credit facilities	0	0	0
Borrowings on revolving credit facilities	0	0	0
Increase (Decrease) in Client Funds Held	0
Payments for Repurchase of Redeemable Noncontrolling Interest	0
Tax withholding payments on behalf of employees	0	0	0
Proceeds from employee stock plans	0	0	0
Debt issuance costs	0
Payments for Repurchase of Common Stock	0	0
Other financing activities	0	0	0
Dividend distribution to consolidated subsidiaries	0	0	0
Equity contribution	(14)	0	(10)
Borrowings (repayments) of intercompany notes	(35)	0	(2)
Net Cash Provided by (Used in) Financing Activities	(49)	0
Payments to Noncontrolling Interests			0
Net Cash Provided by (Used in) Financing Activities			(12)
Net cash used in discontinued operations operating activities	0	0	0
Effect of Exchange Rate changes on cash and cash equivalents	0	0	0
Decrease in cash, cash equivalents, and restricted cash	0	1	0
Restricted Cash	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash	3	3	2	2
Non-Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	412	375	483
Expenditures for property, plant and equipment	(48)	(34)	(41)
Proceeds from Sale of property, plant, and equipment	8	2	6
Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties	169	0
Additions to capitalized software	(43)	(26)	(33)
Business acquisitions, net	(112)	0
Proceeds from (payment of) of intercompany notes			2
Payments to Acquire Businesses, Gross			0
Investments in equity affiliates	98	0	0
Other investing activities, net	0	0	4
Net change in funds held for clients - investing	(15)
Net Cash Provided by (Used in) Investing Activities	57	(58)	(62)
Short term borrowings, net	0	0	1
Proceeds from Issuance of Secured Debt	0
Repurchase of Series A Convertible Preferred Stock	0
Proceeds from Issuance of Unsecured Debt	0
Payments on term credit facilities	0	0	(5)
Repayments of Unsecured Debt	0
Payments on revolving credit facilities	(386)	(478)	(240)
Borrowings on revolving credit facilities	635	578	240
Increase (Decrease) in Client Funds Held	(15)
Payments for Repurchase of Redeemable Noncontrolling Interest	(3)
Tax withholding payments on behalf of employees	0	0	0
Proceeds from employee stock plans	0	0	0
Debt issuance costs	0
Payments for Repurchase of Common Stock	0	0
Other financing activities	(3)	0	(2)
Dividend distribution to consolidated subsidiaries	(1)	(18)	(10)
Equity contribution	0	14	(3)
Borrowings (repayments) of intercompany notes	(681)	(363)	(410)
Net Cash Provided by (Used in) Financing Activities	(424)	(267)
Payments to Noncontrolling Interests			0
Net Cash Provided by (Used in) Financing Activities			(429)
Net cash used in discontinued operations operating activities	(2)	0	0
Effect of Exchange Rate changes on cash and cash equivalents	(6)	(24)	15
Decrease in cash, cash equivalents, and restricted cash	37	26	7
Restricted Cash	7	11	6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash	498	461	435	428
Consolidation, Eliminations [Member]
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	(1)	(18)	(10)
Expenditures for property, plant and equipment	0	0	0
Proceeds from Sale of property, plant, and equipment	0	0	0
Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties	(851)	(363)
Additions to capitalized software	0	0	0
Business acquisitions, net	0	0
Proceeds from (payment of) of intercompany notes			(412)
Payments to Acquire Businesses, Gross			0
Investments in equity affiliates	(98)	4	(13)
Other investing activities, net	0	0	0
Net change in funds held for clients - investing	0
Net Cash Provided by (Used in) Investing Activities	(949)	(359)	(425)
Short term borrowings, net	0	0	0
Proceeds from Issuance of Secured Debt	0
Repurchase of Series A Convertible Preferred Stock	0
Proceeds from Issuance of Unsecured Debt	0
Payments on term credit facilities	0	0	0
Repayments of Unsecured Debt	0
Payments on revolving credit facilities	0	0	0
Borrowings on revolving credit facilities	0	0	0
Increase (Decrease) in Client Funds Held	0
Payments for Repurchase of Redeemable Noncontrolling Interest	0
Tax withholding payments on behalf of employees	0	0	0
Proceeds from employee stock plans	0	0	0
Debt issuance costs	0
Payments for Repurchase of Common Stock	0	0
Other financing activities	0	0	0
Dividend distribution to consolidated subsidiaries	1	18	10
Equity contribution	98	(4)	13
Borrowings (repayments) of intercompany notes	851	363	412
Net Cash Provided by (Used in) Financing Activities	950	377
Payments to Noncontrolling Interests			0
Net Cash Provided by (Used in) Financing Activities			435
Net cash used in discontinued operations operating activities	0	0	0
Effect of Exchange Rate changes on cash and cash equivalents	0	0	0
Decrease in cash, cash equivalents, and restricted cash	0	0	0
Restricted Cash	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash	$ 0	$ 0	$ 0	$ 0