Acquisitions and Divestitures - Components of Income From Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating income	$ 62	$ 85	$ 71
Income from discontinued operations, net of tax	0	0	18
Gain on sale of discontinued operations, net of tax	0	0	160
Income from discontinued operations attributable to S&P Global Inc. common shareholders	$ 0	$ 0	178
Discontinued Operations, Disposed of by Sale | McGraw Hill Construction
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue			139
Expenses			110
Operating income			29
Provision for taxes on income			11
Income from discontinued operations, net of tax			18
Pre-tax gain on sale from discontinued operations			289
Provision for taxes on gain on sale			129
Gain on sale of discontinued operations, net of tax			160
Income from discontinued operations attributable to S&P Global Inc. common shareholders			$ 178