Equity (Tables)

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Summary of common stock

	As of December 31, 2016			As of December 31, 2015
(In millions)	Authorized	Issued	Outstanding	Authorized	Issued	Outstanding
Common stock	1,000.0	238.5	215.9	1,000.0	241.2	218.6