Distribution of Total Assets and Operating Performance (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total Assets	$ 116,749.6	$ 109,946.5	$ 102,947.3
Total Revenue	4,702.6	4,331.2	4,089.3
Income Before Income Taxes	1,465.0	1,190.2	1,075.5
Net Income	973.8	811.8	731.3
Non - U.S.
Segment Reporting Information [Line Items]
Total Assets	30,636.5	28,326.1	30,241.3
Total Revenue	1,358.4	1,341.8	1,101.0
Income Before Income Taxes	483.2	446.5	272.4
Net Income	344.4	322.7	201.3
U.S.
Segment Reporting Information [Line Items]
Total Assets	86,113.1	81,620.4	72,706.0
Total Revenue	3,344.2	2,989.4	2,988.3
Income Before Income Taxes	981.8	743.7	803.1
Net Income	$ 629.4	$ 489.1	$ 530.0