Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000.0	100,000.0
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	3,200,000,000	3,200,000,000
Common stock, shares issued (in shares)	1,724,000,000	1,720,000,000
Common stock, shares outstanding (in shares)	1,299,000,000	1,295,000,000
Treasury stock (in shares)	425,000,000	425,000,000