Debt (Tables)

12 Months Ended

Dec. 31, 2017

Debt

Short-Term Debt (Table)

	December 31,
	2017		2016
	(in millions)
Line of credit	$	39.5	$	51.4
Total short-term debt	$	39.5	$	51.4

Long-Term Debt (Table)

	December 31, 2017
	Principal		Net unamortized discount, premium and debt issuance costs			Carrying amount
	(in millions)
3.3% notes payable, due 2022	$	300.0	$	(1.9	)	$	298.1
3.125% notes payable, due 2023		300.0		(1.5	)		298.5
3.4% notes payable, due 2025		400.0		(3.5	)		396.5
3.1% notes payable, due 2026		350.0		(3.1	)		346.9
6.05% notes payable, due 2036		505.6		(2.7	)		502.9
4.625% notes payable, due 2042		300.0		(3.3	)		296.7
4.35% notes payable, due 2043		300.0		(3.4	)		296.6
4.3% notes payable, due 2046		300.0		(3.4	)		296.6
4.7% notes payable, due 2055		400.0		(5.0	)		395.0
Non-recourse mortgages and notes payable		49.0		1.6			50.6
Total long-term debt	$	3,204.6	$	(26.2	)	$	3,178.4

	December 31, 2016
	Principal		Net unamortized discount, premium and debt issuance costs			Carrying amount
	(in millions)
3.3% notes payable, due 2022	$	300.0	$	(2.2	)	$	297.8
3.125% notes payable, due 2023		300.0		(1.8	)		298.2
3.4% notes payable, due 2025		400.0		(3.9	)		396.1
3.1% notes payable, due 2026		350.0		(3.3	)		346.7
6.05% notes payable, due 2036		505.6		(2.7	)		502.9
4.625% notes payable, due 2042		300.0		(3.4	)		296.6
4.35% notes payable, due 2043		300.0		(3.4	)		296.6
4.3% notes payable, due 2046		300.0		(3.5	)		296.5
4.7% notes payable, due 2055		400.0		(5.0	)		395.0
Non-recourse mortgages and notes payable (1)		—		(0.7	)		(0.7	)
Total long-term debt	$	3,155.6	$	(29.9	)	$	3,125.7

  (1) Includes external debt issuance costs incurred for long-term affiliated debt issued in a foreign jurisdiction.

Future Annual Maturities of Long-Term Debt (Table)

        As of December 31, 2017, future annual maturities of long-term debt were as follows (in millions):

Year ending December 31:
2018	$	—
2019		—
2020		—
2021		—
2022		298.2
Thereafter		2,880.2
Total future maturities of long-term debt	$	3,178.4