Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2018

Regulatory Capital Requirements [Abstract]

Summary Of Actual Capital Amounts And Ratios For The Company And Its Three Largest Subsidiary Banks

(Dollar amounts in millions)	December 31, 2018				To be well-capitalized
	Amount		Ratio		Amount		Ratio
Basel III Regulatory Capital Amounts and Ratios1
Total capital (to risk-weighted assets)	$	7,450	13.9	%	$	5,359	10.0	%
Tier 1 capital (to risk-weighted assets)	6,811		12.7		4,287		8.0
Common equity tier 1 capital (to risk-weighted assets)	6,245		11.7		3,483		6.5
Tier 1 capital (to average assets)	6,811		10.3		3,317		5.0

	December 31, 2017				To be well-capitalized
(Dollar amounts in millions)	Amount		Ratio		Amount		Ratio
Basel III Regulatory Capital Amounts and Ratios
Total capital (to risk-weighted assets)
Zions Bancorporation	$	7,628	14.8	%	$	5,146	10.0	%
ZB, National Association	7,306		14.2		5,130		10.0
Tier 1 capital (to risk-weighted assets)
Zions Bancorporation	6,805		13.2		4,116		8.0
ZB, National Association	6,730		13.1		4,104		8.0
Common equity tier 1 capital (to risk-weighted assets)
Zions Bancorporation	6,239		12.1		3,345		6.5
ZB, National Association	5,899		11.5		3,334		6.5
Tier 1 capital (to average assets)
Zions Bancorporation	6,805		10.5		na		na 2
ZB, National Association	6,730		10.4		3,227		5.0

¹  Basel III regulatory capital amounts and ratios for 2018 are for Zions Bancorporation, National Association.

²  There is no Tier 1 leverage ratio component in the definition of a well-capitalized bank holding company.