CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 1,290	$ 1,142
Expenses
Operating	340	342
Selling, general and administrative	301	281
Restructuring	(1)	6
Depreciation and amortization	49	50
Acquisition-Related Expenses	0	1
Loss pursuant to the divestiture of MAKS	9	0
Total expenses	698	680
Operating income	592	462
Non-operating (expense) income, net
Interest expense, net	(40)	(52)
Other non-operating income, net	12	2
Total non-operating expense, net	(28)	(50)
Income before provisions for income taxes	564	412
Provision for income taxes	77	38
Net income	487	374
Less: Net (loss) income attributable to noncontrolling interests	(1)	1
Net income attributable to Moody's	$ 488	$ 373
Earnings per share attributable to Moody's common shareholders
Basic (in usd per share)	$ 2.60	$ 1.96
Diluted (in usd per share)	$ 2.57	$ 1.93
Weighted average number of shares outstanding
Basic (in shares)	187.5	190.4
Diluted (in shares)	189.6	192.8