Accounting Standards ASU 2016-02 Leases and related updates (Details) - Accounting Standards Update 2016-02 [Member] $ in Millions	Jan. 01, 2019 USD ($)
Operating Lease Right Of Use Asset [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 629
Operating Lease Liability [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	629
ANDX LP [Member] | Operating Lease Right Of Use Asset [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	124
ANDX LP [Member] | Operating Lease Liability [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 127