Stockholders Equity (Notes)	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders’ Equity	Stockholders’ EquityOn July 31, 2019, the Board of Directors authorized an extension of the share repurchase program, which increased the remaining share repurchase authorization to $1.5 billion. During 2019, we acquired approximately 24 million of common shares at a cost of $345 million, which were held as treasury stock. During 2018, we acquired 36 million of common shares at a cost of $700 million under the same program. As of December 31, 2019 the total remaining share repurchase authorization was $1.4 billion. Purchases under the program are made at our discretion and may be in either open market transactions, including block purchases, or in privately negotiated transactions using cash on hand, cash generated from operations or proceeds from potential asset sales. This program may be changed based upon our financial condition or changes in market conditions and is subject to termination prior to completion. The repurchase program does not include specific price targets or timetables.