Earnings Per Share - Antidilutive Securities Excluded from Computation of EPS Table (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Common stock equivalent of our convertible senior notes outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock that were excluded from the calculation of diluted EPS (in shares)	146	146	146	146
Participating securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock that were excluded from the calculation of diluted EPS (in shares)	1	1	1	1
Common stock equivalent of our preferred stock outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock that were excluded from the calculation of diluted EPS (in shares)	60	60	60	60