RELATED PARTY TRANSACTIONS AND SIGNIFICANT TRANSACTIONS WITH RBS - Schedule of Related Party Debt Terms (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014	Oct. 08, 2014
Related Party Transaction [Line Items]
Long-term borrowed funds		$ 9,886	$ 4,642
RBSG
Related Party Transaction [Line Items]
Long-term borrowed funds		$ 1,250	$ 2,000
Subordinated Debt | RBSG | 5.158% fixed-to-floating rate subordinated debt, (LIBOR 3.56%) callable, due 2023
Related Party Transaction [Line Items]
Interest rate		5.158%	5.158%
Long-term borrowed funds		$ 333	$ 333
Subordinated Debt | RBSG | 4.771% fixed rate subordinated debt, due 2023
Related Party Transaction [Line Items]
Interest rate		4.771%	4.771%
Long-term borrowed funds		$ 0	$ 333
Subordinated Debt | RBSG | 4.691% fixed rate subordinated debt, due 2024
Related Party Transaction [Line Items]
Interest rate		4.691%	4.691%
Long-term borrowed funds		$ 0	$ 334
Subordinated Debt | RBSG | 4.153% fixed rate subordinated debt due 2024
Related Party Transaction [Line Items]
Interest rate	[1]	4.153%	4.153%
Long-term borrowed funds		$ 250	$ 333
Subordinated Debt | RBSG | 4.023% fixed rate subordinated debt, due 2024
Related Party Transaction [Line Items]
Interest rate		4.023%	4.023%
Long-term borrowed funds		$ 333	$ 333
Subordinated Debt | RBSG | 4.082% fixed rate subordinated debt, due 2025
Related Party Transaction [Line Items]
Interest rate		4.082%	4.082%	4.082%
Long-term borrowed funds		$ 334	$ 334	$ 334
Citizens Financial Group, Inc.
Related Party Transaction [Line Items]
Long-term borrowed funds		$ 2,595
Citizens Financial Group, Inc. | Subordinated Debt | 5.158% fixed-to-floating rate subordinated debt, (LIBOR 3.56%) callable, due 2023
Related Party Transaction [Line Items]
Interest rate	[2]	5.158%
Long-term borrowed funds	[2]	$ 333	333
Citizens Financial Group, Inc. | Subordinated Debt | 4.771% fixed rate subordinated debt, due 2023
Related Party Transaction [Line Items]
Interest rate	[2]	4.771%
Long-term borrowed funds	[2]	$ 0	333
Citizens Financial Group, Inc. | Subordinated Debt | 4.691% fixed rate subordinated debt, due 2024
Related Party Transaction [Line Items]
Interest rate	[2]	4.691%
Long-term borrowed funds	[2]	$ 0	334
Citizens Financial Group, Inc. | Subordinated Debt | 4.153% fixed rate subordinated debt due 2024
Related Party Transaction [Line Items]
Interest rate	[2],[3]	4.153%
Long-term borrowed funds	[2],[3]	$ 250	333
Citizens Financial Group, Inc. | Subordinated Debt | 4.023% fixed rate subordinated debt, due 2024
Related Party Transaction [Line Items]
Interest rate	[2],[4]	4.023%
Long-term borrowed funds	[2],[4]	$ 331	333
Citizens Financial Group, Inc. | Subordinated Debt | 4.082% fixed rate subordinated debt, due 2025
Related Party Transaction [Line Items]
Interest rate	[2],[5]	4.082%
Long-term borrowed funds	[2],[5]	$ 331	$ 334
Citizens Financial Group, Inc. | Subordinated Debt | 3.750% fixed rate subordinated debt due 2024
Related Party Transaction [Line Items]
Interest rate	[2],[3]	3.75%

[1] Interest is payable until January 1, 2016 at a fixed rate per annum of 4.153% and at a fixed rate per annum of 3.750% thereafter.

[2] Borrowed funds with RBS. See Note 19 “Related Party Transactions and Significant Transactions with RBS” for further information.

[3] Interest is payable until January 1, 2016 at a fixed rate per annum of 4.153% and at a fixed rate per annum of 3.750% thereafter.

[4] $333 million principal balance of subordinated debt reflects the impact of $2 million hedge of interest rate risk on medium term debt using interest rate swaps at December 31, 2015. See Note 16 “Derivatives” for further information.

[5] $334 million principal balance of subordinated debt reflects the impact of $3 million hedge of interest rate risk on medium term debt using interest rate swaps at December 31, 2015. See Note 16 “Derivatives” for further information.