Equity - Share Repurchases (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares purchased	0.0	1.1	5.0	2.6
Average price paid per share (in dollars per share)	$ 0.00	$ 137.49	$ 178.11	$ 133.01
Total cash utilized			$ 1,100
Total SPGI Equity
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total cash utilized	$ 0	$ 145	$ 1,100	$ 346

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Total cost of shares repurchased divided by the total number of shares repurchased.

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-Publisher FASB
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Number of shares that have been repurchased during the period and are being held in treasury.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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