Income Taxes - Income Before Income Taxes and Income Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of Income Before Income Taxes
U.S.	$ 2,482	$ 1,739	$ 1,976
Foreign	683	767	185
Income Before Income Taxes	3,165	2,506	2,161
Current tax expense (benefit)
Federal	(2)	(22)	(137)
State	10	(45)	(16)
Foreign(a)	201	249	18
Total	209	182	(135)
Deferred tax expense (benefit)
Federal	682	425	2,022
State	66	55	4
Foreign(a)	(31)	(75)	47
Total	717	405	2,073
Total	926	587	1,938
Canada
Components of Income Tax Provision
Foreign income tax expense	$ 165	$ 168	$ 58

No definition available.

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- Definition

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.7)
-URI http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319