Segments Segments (Segment Balance Sheet Data) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Average Assets	$ 24,666,235	$ 25,031,608
Average Loans, including held for sale	13,945,572	13,629,151
Average Goodwill and other intangible assets	147,108	146,018
Average Deposits	20,131,252	20,594,786
Consumer Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	2,541,627	2,610,045
Average Loans, including held for sale	2,401,657	2,471,578
Average Goodwill and other intangible assets	78,062	76,734
Average Deposits	10,210,506	10,190,613
Commercial Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	9,115,738	8,830,584
Average Loans, including held for sale	8,939,696	8,635,035
Average Goodwill and other intangible assets	68,300	68,538
Average Deposits	8,029,248	8,301,004
Wealth Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	1,243,806	1,218,598
Average Loans, including held for sale	1,233,780	1,209,792
Average Goodwill and other intangible assets	746	746
Average Deposits	1,871,596	2,090,582
Segment Totals [Member]
Segment Reporting Information [Line Items]
Average Assets	12,901,171	12,659,227
Average Loans, including held for sale	12,575,133	12,316,405
Average Goodwill and other intangible assets	147,108	146,018
Average Deposits	20,111,350	20,582,199
Other/Elimination [Member]
Segment Reporting Information [Line Items]
Average Assets	11,765,064	12,372,381
Average Loans, including held for sale	1,370,439	1,312,746
Average Goodwill and other intangible assets	0	0
Average Deposits	$ 19,902	$ 12,587