Equity (Compensation Expense Related to Stock-Based Compensation - Related to Phantom Stock-Based Awards) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	$ 150	$ 86	$ 128
Income tax benefit	32	18	45
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	7	6	8
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	89	23	62
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	$ 54	$ 57	$ 58