Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2020

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of net pension and retiree health benefit (income) cost

Net pension and retiree health benefit (income) cost included the following components:

	Defined Benefit Pension Plans
	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Components of net periodic benefit cost:
Service cost	$	83.0	$	63.5	$	161.7	$	125.4
Interest cost	107.3		122.6		212.3		243.3
Expected return on plan assets	(220.6)		(210.1)		(441.8)		(421.2)
Amortization of prior service cost	1.1		1.5		2.2		3.0
Recognized actuarial loss	117.1		73.1		228.1		142.7
Net periodic benefit cost	$	87.9	$	50.6	$	162.5	$	93.2

	Retiree Health Benefit Plans
	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Components of net periodic benefit income:
Service cost	$	10.6	$	9.4	$	20.4	$	18.2
Interest cost	10.9		14.4		21.9		29.0
Expected return on plan assets	(37.4)		(36.0)		(74.8)		(71.9)
Amortization of prior service benefit	(14.9)		(15.7)		(29.8)		(31.5)
Recognized actuarial loss	0.6		0.4		1.4		0.9
Net periodic benefit income	$	(30.2)	$	(27.5)	$	(60.9)	$	(55.3)