Pension Benefit Plans (Summary Of Changes In Fair Value Of Level 3 Investments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	$ 2,378.3	$ 1,480.3
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	165.0	158.8
Actual return on plan assets relating to assets sold during the period	0.9	(1.1)
Actual return on plan assets relating to assets still held at end of period	(7.4)	1.7
Acquisitions	154.4	9.9
Purchases, sales, issuances and settlements	9.3	(4.3)
Sales	(3.7)
Settlements	(2.6)
Fair value of plan assets at end of year	315.9	165.0
Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	348.6	376.9
Common Stock [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0.7	6.4
Actual return on plan assets relating to assets sold during the period		(0.1)
Actual return on plan assets relating to assets still held at end of period		0.5
Purchases, sales, issuances and settlements		(6.1)
Sales	(0.7)
Fair value of plan assets at end of year		0.7
Venture Capital And Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	163.9	62.6
Venture Capital And Partnerships [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	62.6	52.2
Actual return on plan assets relating to assets sold during the period		(1.0)
Actual return on plan assets relating to assets still held at end of period	(16.0)	1.9
Acquisitions	114.2	9.9
Purchases, sales, issuances and settlements	7.0	(0.4)
Sales	(1.3)
Settlements	(2.6)
Fair value of plan assets at end of year	163.9	62.6
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	152.0	101.7
Real Estate [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	101.7	100.2
Actual return on plan assets relating to assets sold during the period	0.9
Actual return on plan assets relating to assets still held at end of period	8.6	(0.7)
Acquisitions	40.2
Purchases, sales, issuances and settlements	2.3	2.2
Sales	(1.7)
Fair value of plan assets at end of year	$ 152.0	$ 101.7