Restructuring - Summary (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Operating Segments | Ratings
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded		$ 11		$ 11
Operating Segments | Market Intelligence
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded		1	$ 2	1
Operating Segments | Platts
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded		1		1
Corporate
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded	$ 3	$ 7	10	$ 7
2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			12
Ending Reserve Balance	8		8
2020 Restructuring Plan | Operating Segments | Ratings
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			0
Ending Reserve Balance	0		0
2020 Restructuring Plan | Operating Segments | Market Intelligence
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			2
Ending Reserve Balance	1		1
2020 Restructuring Plan | Operating Segments | Platts
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			0
Ending Reserve Balance	0		0
2020 Restructuring Plan | Corporate
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			10
Ending Reserve Balance	7		7
2019 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			25
Ending Reserve Balance	7		7		$ 18
2019 Restructuring Plan | Operating Segments | Ratings
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			11
Ending Reserve Balance	1		1
2019 Restructuring Plan | Operating Segments | Market Intelligence
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			6
Ending Reserve Balance	3		3
2019 Restructuring Plan | Operating Segments | Platts
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			1
Ending Reserve Balance	0		0
2019 Restructuring Plan | Corporate
Restructuring Cost and Reserve [Line Items]
Initial Charge Recorded			7
Ending Reserve Balance	$ 3		$ 3