Equity Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax Beginning Balance	$ (240,400,000)	$ (318,400,000)	$ (319,900,000)
Balance, January 1, 2018	(240,400,000)	(318,400,000)	(318,400,000)	$ (316,900,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	230,800,000	29,500,000	(42,700,000)
Amounts Reclassified From Accumulated Other Comprehensive Income, Net of Tax	(125,600,000)	47,000,000.0	44,200,000
Other comprehensive income (loss), net of tax	105,200,000	76,500,000	1,500,000
Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance	(135,200,000)	(240,400,000)	(318,400,000)
Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax Beginning Balance	(4,000,000.0)	(1,600,000)	(10,800,000)
Balance, January 1, 2018	(4,000,000.0)	(1,600,000)	(1,600,000)	(100,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	11,800,000	(10,600,000)	(3,500,000)
Amounts Reclassified From Accumulated Other Comprehensive Income, Net of Tax	(3,600,000)	6,700,000	12,700,000
Other comprehensive income (loss), net of tax	8,200,000	(3,900,000)	9,200,000
Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance	4,200,000	(4,000,000.0)	(1,600,000)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax Beginning Balance	34,700,000	(104,500,000)	57,800,000
Balance, January 1, 2018	7,800,000	(104,500,000)	57,800,000	(104,500,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	88,100,000	97,400,000	(193,800,000)
Amounts Reclassified From Accumulated Other Comprehensive Income, Net of Tax	(115,000,000.0)	41,800,000	31,500,000
Other comprehensive income (loss), net of tax	(26,900,000)	139,200,000	(162,300,000)
Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance	7,800,000	34,700,000	(104,500,000)
Gains (Losses) on Net Investment Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax Beginning Balance	3,500,000	0	0
Balance, January 1, 2018	3,500,000	3,500,000	0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	28,600,000	5,000,000.0	0
Amounts Reclassified From Accumulated Other Comprehensive Income, Net of Tax	(7,000,000.0)	(1,500,000)	0
Other comprehensive income (loss), net of tax	21,600,000	3,500,000	0
Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance	25,100,000	3,500,000	0
Unfunded Status of Post Retirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax Beginning Balance	(31,300,000)	(36,800,000)	(32,700,000)
Balance, January 1, 2018	(32,800,000)	(36,800,000)	(36,800,000)	(36,800,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(1,500,000)	5,500,000	(4,100,000)
Amounts Reclassified From Accumulated Other Comprehensive Income, Net of Tax	0	0	0
Other comprehensive income (loss), net of tax	(1,500,000)	5,500,000	(4,100,000)
Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance	(32,800,000)	(31,300,000)	(36,800,000)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax Beginning Balance	(243,300,000)	(175,500,000)	(334,200,000)
Balance, January 1, 2018	(243,300,000)	(243,300,000)	(334,200,000)	(175,500,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	103,800,000	(67,800,000)	158,700,000
Amounts Reclassified From Accumulated Other Comprehensive Income, Net of Tax	0	0	0
Other comprehensive income (loss), net of tax	103,800,000	(67,800,000)	158,700,000
Accumulated Other Comprehensive Income (Loss), Net of Tax Ending Balance	$ (139,500,000)	$ (243,300,000)	$ (175,500,000)
Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				1,500,000
Accounting Standards Update 2016-01 | Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				1,500,000
Accounting Standards Update 2016-01 | Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				0
Accounting Standards Update 2016-01 | Gains (Losses) on Net Investment Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				0
Accounting Standards Update 2016-01 | Unfunded Status of Post Retirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				0
Accounting Standards Update 2016-01 | Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ 0