Divestitures - Narrative (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 18, 2017	Nov. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Aug. 01, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from sale of business, pre-tax			$ 0	$ 109	$ 0	$ 109
Enterprise Information Solutions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from sale of business, pre-tax				109
Gain from sale of business, after tax				30
Enterprise Information Solutions | Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price agreed to for sell of EIS business								$ 185
Goodwill							$ 124
Assets							243
Liabilities							$ 190
Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of equity method investment		$ 61
Pre-tax gain on sale of equity method investments			56		56
After-tax gain on sale of equity method investments			$ 41		$ 41
Cash consideration received after exercising option under the agreement		23
Portion of proceeds used to obtain equity interest in new entity		$ 38
European Pharmaceutical Solutions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of equity method investment	$ 42
Pre-tax gain on sale of equity method investments				43		43
After-tax gain on sale of equity method investments				$ 26		$ 26