Nonoperating Income (Expense) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Apr. 01, 2016	Sep. 29, 2017	Sep. 30, 2016
Component of Operating Income [Abstract]
Proceeds from sale of marketable securities			$ 265.0	$ 0.0	$ 264.8
Marketable securities, realized gain					223.0
Marketable securities, after-tax realized gain					$ 140.0
Marketable securities, after-tax gain, per diluted share					$ 0.20
Extinguishment of debt, amount		$ 1,900.0
Make-whole premiums to redeem borrowings prior to maturity		(188.0)		0.0	$ (188.1)
Extinguishment of debt, deferred gains		9.0			9.3
Pretax loss on early extinguishment of borrowings	$ 0.0	(178.8)		$ 0.0	$ (178.8)
Extinguishment of debt, loss, net of tax		$ (112.0)
Extinguishment of debt, loss, per share, net of tax		$ (0.16)