Condensed Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets, Current [Abstract]
Cash and cash equivalents	$ 488	$ 496
Accounts Receivable, after Allowance for Credit Loss, Current	687	652
Contract with Customer, Asset, Net, Current	166	155
Other current assets	312	283
Total current assets	1,653	1,586
Assets
Land, buildings and equipment, net	306	342
Operating Lease, Right-of-Use Asset	246	271
Intangible assets, net	247	426
Goodwill	1,506	1,502
Other long-term assets	402	387
Total Assets	4,360	4,514
Liabilities, Current [Abstract]
Current portion of long-term debt	78	50
Accounts payable	173	198
Accrued compensation and benefits costs	200	174
Unearned income	112	108
Other current liabilities	478	647
Total current liabilities	1,041	1,177
Long-term debt	1,574	1,464
Deferred Income Tax Liabilities, Net	106	111
Operating Lease, Liability, Noncurrent	209	229
Other long-term liabilities	105	91
Total Liabilities	3,035	3,072
Contingencies (See Note 11)
Series A Convertible Preferred Stock	142	142
Common Stock	2	2
Additional paid-in-capital	3,901	3,890
Retained earnings	(2,299)	(2,185)
Accumulated other comprehensive loss	(421)	(407)
Total Equity	1,183	1,300
Total Liabilities and Equity	$ 4,360	$ 4,514
Shares of common stock outstanding (in shares)	209,273	211,511
Shares of series A convertible preferred stock outstanding (in shares)	120	120