Significant Accounting Policies (Schedule of Impact of New Accounting Pronouncements) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018
Assets
Operating lease right-of-use asset	$ 175	$ 185	$ 0
Other current assets		107	108
Deferred income taxes		215	222
Equity in and advances to unconsolidated affiliates	850		724	$ 452
Liabilities
Operating lease liabilities	39	40	0
Other current liabilities	186	174	179
Operating lease liabilities (noncurrent)	192	213	0
Other liabilities (noncurrent)	124	110	202	172
Shareholders' equity
Retained Earnings	$ 1,441	1,256	$ 1,235	$ 998
Adjustments Due to Topic 842
Assets
Operating lease right-of-use asset		185
Other current assets		(1)
Deferred income taxes		7
Liabilities
Operating lease liabilities		40
Other current liabilities		(5)
Operating lease liabilities (noncurrent)		213
Other liabilities (noncurrent)		(92)
Shareholders' equity
Retained Earnings		$ 21