Capital and Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2020

Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]

The following table presents actual and required capital ratios as of December 31, 2020 and December 31, 2019 for Cullen/Frost and Frost Bank under the Basel III Capital Rules. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules.


	Actual				Minimum Capital Required - Basel III Fully Phased-In				Required to be Considered Well Capitalized
	Capital Amount		Ratio		Capital Amount		Ratio		Capital Amount		Ratio
2020
Common Equity Tier 1 to Risk-Weighted Assets
Cullen/Frost	$	3,058,447	12.86	%	$	1,664,867	7.00	%	$	1,545,948	6.50	%
Frost Bank	3,030,093		12.77		1,661,620		7.00		1,542,933		6.50
Tier 1 Capital to Risk-Weighted Assets
Cullen/Frost	3,203,899		13.47		2,021,624		8.50		1,902,705		8.00
Frost Bank	3,030,093		12.77		2,017,682		8.50		1,898,995		8.00
Total Capital to Risk-Weighted Assets
Cullen/Frost	3,672,912		15.44		2,497,300		10.50		2,378,381		10.00
Frost Bank	3,266,106		13.76		2,492,430		10.50		2,373,743		10.00
Leverage Ratio
Cullen/Frost	3,203,899		8.07		1,589,004		4.00		1,986,255		5.00
Frost Bank	3,030,093		7.63		1,588,200		4.00		1,985,250		5.00




2019
Common Equity Tier 1 to Risk-Weighted Assets
Cullen/Frost	$	2,857,250	12.36	%	$	1,617,886	7.00	%	$	1,502,323	6.50	%
Frost Bank	2,958,326		12.82		1,615,206		7.00		1,499,834		6.50
Tier 1 Capital to Risk-Weighted Assets
Cullen/Frost	3,001,736		12.99		1,964,576		8.50		1,849,013		8.00
Frost Bank	2,958,326		12.82		1,961,322		8.50		1,845,950		8.00
Total Capital to Risk-Weighted Assets
Cullen/Frost	3,367,403		14.57		2,426,829		10.50		2,311,266		10.00
Frost Bank	3,090,993		13.40		2,422,809		10.50		2,307,438		10.00
Leverage Ratio
Cullen/Frost	3,001,736		9.28		1,293,188		4.00		1,616,485		5.00
Frost Bank	2,958,326		9.15		1,292,743		4.00		1,615,929		5.00