Condensed Consolidating Financial Statements - Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,756	$ 2,779	$ 2,411	$ 2,392
Accounts receivable, net of allowance for doubtful accounts	1,313	1,319
Intercompany receivable	0	0
Prepaid and other current assets	215	226
Total current assets	3,284	4,324
Property and equipment, net of accumulated depreciation	270	275
Goodwill	3,045	2,989
Other intangible assets, net	1,390	1,388
Investments in subsidiaries	0	0
Intercompany loans receivable	0	0
Other non-current assets	508	449
Total assets	8,497	9,425
Current liabilities:
Accounts payable	196	195
Intercompany payable	0	0
Accrued compensation and contributions to retirement plans	195	472
Short-term debt	400	399
Income taxes currently payable	100	77
Unearned revenue	1,679	1,613
Accrued legal settlements	82	107
Other current liabilities	483	351
Total current liabilities	3,135	3,214
Long-term debt	3,170	3,170
Intercompany loans payable	0	0
Pension and other postretirement benefits	235	244
Other non-current liabilities	539	679
Total liabilities	7,079	7,307
Redeemable noncontrolling interest	1,350	1,350
Equity:
Common stock	412	412
Additional paid-in capital	335	525
Retained income	10,427	10,025
Accumulated other comprehensive loss	(630)	(649)
Less: common stock in treasury	(10,537)	(9,602)
Total equity — controlling interests	7	711
Total equity - noncontrolling interests	61	57
Total equity	68	768
Total liabilities and equity	8,497	9,425
Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Accounts receivable, net of allowance for doubtful accounts	0	0
Intercompany receivable	(4,949)	(5,079)
Prepaid and other current assets	0	0
Total current assets	(4,949)	(5,079)
Property and equipment, net of accumulated depreciation		0
Goodwill	9	9
Other intangible assets, net	0	0
Investments in subsidiaries	(15,159)	(16,397)
Intercompany loans receivable	(2,003)	(1,815)
Other non-current assets	0	(1)
Total assets	(22,102)	(23,283)
Current liabilities:
Accounts payable	0	0
Intercompany payable	(4,949)	(5,079)
Accrued compensation and contributions to retirement plans	0	0
Short-term debt	0	0
Income taxes currently payable	0	0
Unearned revenue	0	0
Accrued legal settlements	0	0
Other current liabilities	0	0
Total current liabilities	(4,949)	(5,079)
Long-term debt	0	0
Intercompany loans payable	(2,003)	(1,816)
Pension and other postretirement benefits	0	0
Other non-current liabilities	0	0
Total liabilities	(6,952)	(6,895)
Redeemable noncontrolling interest	1,350	1,350
Equity:
Common stock	(2,318)	(2,318)
Additional paid-in capital	(9,189)	(9,117)
Retained income	(5,117)	(6,429)
Accumulated other comprehensive loss	41	46
Less: common stock in treasury	23	23
Total equity — controlling interests	(16,560)	(17,795)
Total equity - noncontrolling interests	60	57
Total equity	(16,500)	(17,738)
Total liabilities and equity	(22,102)	(23,283)
S&P Global Inc. | Reportable Legal Entities
Current assets:
Cash and cash equivalents	581	632	627	711
Accounts receivable, net of allowance for doubtful accounts	133	138
Intercompany receivable	608	768
Prepaid and other current assets	92	143
Total current assets	1,414	1,681
Property and equipment, net of accumulated depreciation	170	158
Goodwill	261	261
Other intangible assets, net	0	0
Investments in subsidiaries	7,069	8,364
Intercompany loans receivable	118	116
Other non-current assets	232	215
Total assets	9,264	10,795
Current liabilities:
Accounts payable	79	79
Intercompany payable	3,577	3,433
Accrued compensation and contributions to retirement plans	84	145
Short-term debt	400	399
Income taxes currently payable	13	2
Unearned revenue	288	293
Accrued legal settlements	0	0
Other current liabilities	265	136
Total current liabilities	4,706	4,487
Long-term debt	3,170	3,170
Intercompany loans payable	102	101
Pension and other postretirement benefits	178	180
Other non-current liabilities	157	376
Total liabilities	8,313	8,314
Redeemable noncontrolling interest	0	0
Equity:
Common stock	412	412
Additional paid-in capital	(415)	(216)
Retained income	11,780	12,156
Accumulated other comprehensive loss	(289)	(269)
Less: common stock in treasury	(10,537)	(9,602)
Total equity — controlling interests	951	2,481
Total equity - noncontrolling interests	0	0
Total equity	951	2,481
Total liabilities and equity	9,264	10,795
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Current assets:
Cash and cash equivalents	0	0	0	0
Accounts receivable, net of allowance for doubtful accounts	178	152
Intercompany receivable	1,454	1,784
Prepaid and other current assets	(4)	(3)
Total current assets	1,628	1,933
Property and equipment, net of accumulated depreciation	1	10
Goodwill	0	0
Other intangible assets, net	0	0
Investments in subsidiaries	5	5
Intercompany loans receivable	0	0
Other non-current assets	63	61
Total assets	1,697	2,009
Current liabilities:
Accounts payable	19	23
Intercompany payable	29	492
Accrued compensation and contributions to retirement plans	14	86
Short-term debt	0	0
Income taxes currently payable	0	0
Unearned revenue	247	193
Accrued legal settlements	0	2
Other current liabilities	21	21
Total current liabilities	330	817
Long-term debt	0	0
Intercompany loans payable	0	0
Pension and other postretirement benefits	0	0
Other non-current liabilities	55	74
Total liabilities	385	891
Redeemable noncontrolling interest	0	0
Equity:
Common stock	0	0
Additional paid-in capital	604	602
Retained income	708	516
Accumulated other comprehensive loss	0	0
Less: common stock in treasury	0	0
Total equity — controlling interests	1,312	1,118
Total equity - noncontrolling interests	0	0
Total equity	1,312	1,118
Total liabilities and equity	1,697	2,009
Non-Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash and cash equivalents	1,175	2,147	$ 1,784	$ 1,681
Accounts receivable, net of allowance for doubtful accounts	1,002	1,029
Intercompany receivable	2,887	2,527
Prepaid and other current assets	127	86
Total current assets	5,191	5,789
Property and equipment, net of accumulated depreciation	99	107
Goodwill	2,775	2,719
Other intangible assets, net	1,390	1,388
Investments in subsidiaries	8,085	8,028
Intercompany loans receivable	1,885	1,699
Other non-current assets	213	174
Total assets	19,638	19,904
Current liabilities:
Accounts payable	98	93
Intercompany payable	1,343	1,154
Accrued compensation and contributions to retirement plans	97	241
Short-term debt	0	0
Income taxes currently payable	87	75
Unearned revenue	1,144	1,127
Accrued legal settlements	82	105
Other current liabilities	197	194
Total current liabilities	3,048	2,989
Long-term debt	0	0
Intercompany loans payable	1,901	1,715
Pension and other postretirement benefits	57	64
Other non-current liabilities	327	229
Total liabilities	5,333	4,997
Redeemable noncontrolling interest	0	0
Equity:
Common stock	2,318	2,318
Additional paid-in capital	9,335	9,256
Retained income	3,056	3,782
Accumulated other comprehensive loss	(382)	(426)
Less: common stock in treasury	(23)	(23)
Total equity — controlling interests	14,304	14,907
Total equity - noncontrolling interests	1	0
Total equity	14,305	14,907
Total liabilities and equity	$ 19,638	$ 19,904