Line of Business Results (Tables)

12 Months Ended

Dec. 31, 2016

Segment Reporting [Abstract]

Financial Information of Business Groups

Year ended December 31,	Key Community Bank									Key Corporate Bank
dollars in millions	2016			2015			2014			2016			2015			2014
SUMMARY OF OPERATIONS
Net interest income (TE)	$	1,947		$	1,487		$	1,447		$	1,048		$	887		$	842
Noninterest income	925			788			769			1,014			926			807
Total revenue (TE) (a)	2,872			2,275			2,216			2,062			1,813			1,649
Provision for credit losses	147			70			59			120			103			14
Depreciation and amortization expense	75			56			65			60			43			31
Other noninterest expense	2,056			1,729			1,696			1,067			940			843
Income (loss) from continuing operations before income taxes (TE)	594			420			396			815			727			761
Allocated income taxes (benefit) and TE adjustments	221			156			147			183			190			215
Income (loss) from continuing operations	373			264			249			632			537			546
Income (loss) from discontinued operations, net of taxes	—			—			—			—			—			—
Net income (loss)	373			264			249			632			537			546
Less: Net income (loss) attributable to noncontrolling interests	—			—			—			(2		)	1			2
Net income (loss) attributable to Key	$	373		$	264		$	249		$	634		$	536		$	544
AVERAGE BALANCES (b)
Loans and leases	$	37,613		$	30,834		$	30,105		$	31,935		$	25,865		$	22,978
Total assets (a)	40,284			32,948			32,241			37,801			31,546			28,070
Deposits	63,895			51,163			50,316			20,783			19,043			17,094
OTHER FINANCIAL DATA
Expenditures for additions to long-lived assets (a), (b)	$	1,478		$	75		$	45		$	340		$	16		$	102
Net loan charge-offs (b)	114			92			117			83			40			(18		)
Return on average allocated equity (b)	10.87		%	9.80		%	9.14		%	26.85		%	28.57		%	33.56		%
Return on average allocated equity	10.87			9.80			9.14			26.85			28.57			33.56
Average full-time equivalent employees (c)	8,928			7,520			7,761			2,248			2,100			1,975

(a) Substantially all revenue generated by our major business segments is derived from clients that reside in the United States. Substantially all long-lived assets, including premises and equipment, capitalized software, and goodwill held by our major business segments, are located in the United States.

(b) From continuing operations.

(c) The number of average full-time equivalent employees was not adjusted for discontinued operations.

Other Segments									Total Segments									Reconciling Items									Key
2016			2015			2014			2016			2015			2014			2016			2015			2014			2016			2015			2014
$	(44	)	$	(8	)	$	23		$	2,951		$	2,366		$	2,312		$	2		$	10		$	5		$	2,953		$	2,376		$	2,317
153			183			231			2,092			1,897			1,807			(21		)	(17		)	(10		)	2,071			1,880			1,797
109			175			254			5,043			4,263			4,119			(19		)	(7		)	(5		)	5,024			4,256			4,114
(4		)	(8		)	(15		)	263			165			58			3			1			(1		)	266			166			57
4			8			12			139			107			108			164			148			152			303			255			260
44			47			70			3,167			2,716			2,609			286			(131		)	(108		)	3,453			2,585			2,501
65			128			187			1,474			1,275			1,344			(472		)	(25		)	(48		)	1,002			1,250			1,296
(20		)	—			26			384			346			388			(171		)	(15		)	(38		)	213			331			350
85			128			161			1,090			929			956			(301		)	(10		)	(10		)	789			919			946
—			—			—			—			—			—			1			1			(39		)	1			1			(39		)
85			128			161			1,090			929			956			(300		)	(9		)	(49		)	790			920			907
2			3			5			—			4			7			(1		)	—			—			(1		)	4			7
$	83		$	125		$	156		$	1,090		$	925		$	949		$	(299	)	$	(9	)	$	(49	)	$	791		$	916		$	900
$	1,477		$	1,852		$	2,528		$	71,025		$	58,551		$	55,611		$	123		$	43		$	68		$	71,148		$	58,594		$	55,679
33,565			26,935			26,113			111,650			91,429			86,424			887			597			655			112,537			92,026			87,079
1,481			467			579			86,159			70,673			67,989			193			(43		)	(124		)	86,352			70,630			67,865
—			—			—			$	1,818		$	91		$	147		$	116		$	48		$	118		$	1,934		$	139		$	265
$	7		$	9		$	14		204			141			113			1			1			—			205			142			113
47.43		%	58.96		%	55.71		%	18.27		%	19.34		%	20.52		%	(4.49		)%	(.17		)%	(.17		)%	6.25		%	8.61		%	8.97		%
47.43			58.96			55.71			18.27			19.34			20.52			(4.48		)	(.15		)	(.84		)	6.25			8.61			8.59
10			14			42			11,186			9,634			9,778			4,514			3,849			4,075			15,700			13,483			13,853