Fair Value Measurements (Aggregate Fair Value of Derivative Financial Instruments, Equity Securities and Debt (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Liabilities:
Equity securities, unrealized gain (loss)	$ (78)
Equity securities, unrealized gain (loss), net	(62)
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Assets:
Equity securities	252
Derivative contracts	0
Total assets	252
Liabilities:
Debt	32,572
Derivative contracts	0
Total liabilities	32,572
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Equity securities	0
Derivative contracts	322
Total assets	322
Liabilities:
Debt	169
Derivative contracts	255
Total liabilities	424
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Equity securities	0
Derivative contracts	0
Total assets	0
Liabilities:
Debt	0
Derivative contracts	0
Total liabilities	0
Fair Value [Member]
Assets:
Equity securities	252
Derivative contracts	322
Total assets	574
Liabilities:
Debt	32,741
Derivative contracts	255
Total liabilities	$ 32,996